From fd08ddb9cb050182c0f7c9d74b11038e9c479f4f Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sun, 14 Nov 2021 11:35:36 +0100 Subject: [PATCH 1/5] linux-user: Split out do_getdents, do_getdents64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Retain all 3 implementations of getdents for now. Signed-off-by: Richard Henderson Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20211114103539.298686-2-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier --- linux-user/syscall.c | 325 +++++++++++++++++++++++-------------------- 1 file changed, 172 insertions(+), 153 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 544f5b662f..a2f605dec4 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -8137,6 +8137,176 @@ static int host_to_target_cpu_mask(const unsigned long *host_mask, return 0; } +#ifdef TARGET_NR_getdents +static int do_getdents(abi_long arg1, abi_long arg2, abi_long arg3) +{ + int ret; + +#ifdef EMULATE_GETDENTS_WITH_GETDENTS +# if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64 + struct target_dirent *target_dirp; + struct linux_dirent *dirp; + abi_long count = arg3; + + dirp = g_try_malloc(count); + if (!dirp) { + return -TARGET_ENOMEM; + } + + ret = get_errno(sys_getdents(arg1, dirp, count)); + if (!is_error(ret)) { + struct linux_dirent *de; + struct target_dirent *tde; + int len = ret; + int reclen, treclen; + int count1, tnamelen; + + count1 = 0; + de = dirp; + target_dirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!target_dirp) { + return -TARGET_EFAULT; + } + tde = target_dirp; + while (len > 0) { + reclen = de->d_reclen; + tnamelen = reclen - offsetof(struct linux_dirent, d_name); + assert(tnamelen >= 0); + treclen = tnamelen + offsetof(struct target_dirent, d_name); + assert(count1 + treclen <= count); + tde->d_reclen = tswap16(treclen); + tde->d_ino = tswapal(de->d_ino); + tde->d_off = tswapal(de->d_off); + memcpy(tde->d_name, de->d_name, tnamelen); + de = (struct linux_dirent *)((char *)de + reclen); + len -= reclen; + tde = (struct target_dirent *)((char *)tde + treclen); + count1 += treclen; + } + ret = count1; + unlock_user(target_dirp, arg2, ret); + } + g_free(dirp); +# else + struct linux_dirent *dirp; + abi_long count = arg3; + + dirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!dirp) { + return -TARGET_EFAULT; + } + ret = get_errno(sys_getdents(arg1, dirp, count)); + if (!is_error(ret)) { + struct linux_dirent *de; + int len = ret; + int reclen; + de = dirp; + while (len > 0) { + reclen = de->d_reclen; + if (reclen > len) { + break; + } + de->d_reclen = tswap16(reclen); + tswapls(&de->d_ino); + tswapls(&de->d_off); + de = (struct linux_dirent *)((char *)de + reclen); + len -= reclen; + } + } + unlock_user(dirp, arg2, ret); +# endif +#else + /* Implement getdents in terms of getdents64 */ + struct linux_dirent64 *dirp; + abi_long count = arg3; + + dirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!dirp) { + return -TARGET_EFAULT; + } + ret = get_errno(sys_getdents64(arg1, dirp, count)); + if (!is_error(ret)) { + /* + * Convert the dirent64 structs to target dirent. We do this + * in-place, since we can guarantee that a target_dirent is no + * larger than a dirent64; however this means we have to be + * careful to read everything before writing in the new format. + */ + struct linux_dirent64 *de; + struct target_dirent *tde; + int len = ret; + int tlen = 0; + + de = dirp; + tde = (struct target_dirent *)dirp; + while (len > 0) { + int namelen, treclen; + int reclen = de->d_reclen; + uint64_t ino = de->d_ino; + int64_t off = de->d_off; + uint8_t type = de->d_type; + + namelen = strlen(de->d_name); + treclen = offsetof(struct target_dirent, d_name) + namelen + 2; + treclen = QEMU_ALIGN_UP(treclen, sizeof(abi_long)); + + memmove(tde->d_name, de->d_name, namelen + 1); + tde->d_ino = tswapal(ino); + tde->d_off = tswapal(off); + tde->d_reclen = tswap16(treclen); + /* + * The target_dirent type is in what was formerly a padding + * byte at the end of the structure: + */ + *(((char *)tde) + treclen - 1) = type; + + de = (struct linux_dirent64 *)((char *)de + reclen); + tde = (struct target_dirent *)((char *)tde + treclen); + len -= reclen; + tlen += treclen; + } + ret = tlen; + } + unlock_user(dirp, arg2, ret); +#endif + return ret; +} +#endif /* TARGET_NR_getdents */ + +#if defined(TARGET_NR_getdents64) && defined(__NR_getdents64) +static int do_getdents64(abi_long arg1, abi_long arg2, abi_long arg3) +{ + struct linux_dirent64 *dirp; + abi_long count = arg3; + int ret; + + dirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!dirp) { + return -TARGET_EFAULT; + } + ret = get_errno(sys_getdents64(arg1, dirp, count)); + if (!is_error(ret)) { + struct linux_dirent64 *de; + int len = ret; + int reclen; + de = dirp; + while (len > 0) { + reclen = de->d_reclen; + if (reclen > len) { + break; + } + de->d_reclen = tswap16(reclen); + tswap64s((uint64_t *)&de->d_ino); + tswap64s((uint64_t *)&de->d_off); + de = (struct linux_dirent64 *)((char *)de + reclen); + len -= reclen; + } + } + unlock_user(dirp, arg2, ret); + return ret; +} +#endif /* TARGET_NR_getdents64 */ + #if defined(TARGET_NR_pivot_root) && defined(__NR_pivot_root) _syscall2(int, pivot_root, const char *, new_root, const char *, put_old) #endif @@ -10227,162 +10397,11 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1, #endif #ifdef TARGET_NR_getdents case TARGET_NR_getdents: -#ifdef EMULATE_GETDENTS_WITH_GETDENTS -#if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64 - { - struct target_dirent *target_dirp; - struct linux_dirent *dirp; - abi_long count = arg3; - - dirp = g_try_malloc(count); - if (!dirp) { - return -TARGET_ENOMEM; - } - - ret = get_errno(sys_getdents(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent *de; - struct target_dirent *tde; - int len = ret; - int reclen, treclen; - int count1, tnamelen; - - count1 = 0; - de = dirp; - if (!(target_dirp = lock_user(VERIFY_WRITE, arg2, count, 0))) - return -TARGET_EFAULT; - tde = target_dirp; - while (len > 0) { - reclen = de->d_reclen; - tnamelen = reclen - offsetof(struct linux_dirent, d_name); - assert(tnamelen >= 0); - treclen = tnamelen + offsetof(struct target_dirent, d_name); - assert(count1 + treclen <= count); - tde->d_reclen = tswap16(treclen); - tde->d_ino = tswapal(de->d_ino); - tde->d_off = tswapal(de->d_off); - memcpy(tde->d_name, de->d_name, tnamelen); - de = (struct linux_dirent *)((char *)de + reclen); - len -= reclen; - tde = (struct target_dirent *)((char *)tde + treclen); - count1 += treclen; - } - ret = count1; - unlock_user(target_dirp, arg2, ret); - } - g_free(dirp); - } -#else - { - struct linux_dirent *dirp; - abi_long count = arg3; - - if (!(dirp = lock_user(VERIFY_WRITE, arg2, count, 0))) - return -TARGET_EFAULT; - ret = get_errno(sys_getdents(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent *de; - int len = ret; - int reclen; - de = dirp; - while (len > 0) { - reclen = de->d_reclen; - if (reclen > len) - break; - de->d_reclen = tswap16(reclen); - tswapls(&de->d_ino); - tswapls(&de->d_off); - de = (struct linux_dirent *)((char *)de + reclen); - len -= reclen; - } - } - unlock_user(dirp, arg2, ret); - } -#endif -#else - /* Implement getdents in terms of getdents64 */ - { - struct linux_dirent64 *dirp; - abi_long count = arg3; - - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { - return -TARGET_EFAULT; - } - ret = get_errno(sys_getdents64(arg1, dirp, count)); - if (!is_error(ret)) { - /* Convert the dirent64 structs to target dirent. We do this - * in-place, since we can guarantee that a target_dirent is no - * larger than a dirent64; however this means we have to be - * careful to read everything before writing in the new format. - */ - struct linux_dirent64 *de; - struct target_dirent *tde; - int len = ret; - int tlen = 0; - - de = dirp; - tde = (struct target_dirent *)dirp; - while (len > 0) { - int namelen, treclen; - int reclen = de->d_reclen; - uint64_t ino = de->d_ino; - int64_t off = de->d_off; - uint8_t type = de->d_type; - - namelen = strlen(de->d_name); - treclen = offsetof(struct target_dirent, d_name) - + namelen + 2; - treclen = QEMU_ALIGN_UP(treclen, sizeof(abi_long)); - - memmove(tde->d_name, de->d_name, namelen + 1); - tde->d_ino = tswapal(ino); - tde->d_off = tswapal(off); - tde->d_reclen = tswap16(treclen); - /* The target_dirent type is in what was formerly a padding - * byte at the end of the structure: - */ - *(((char *)tde) + treclen - 1) = type; - - de = (struct linux_dirent64 *)((char *)de + reclen); - tde = (struct target_dirent *)((char *)tde + treclen); - len -= reclen; - tlen += treclen; - } - ret = tlen; - } - unlock_user(dirp, arg2, ret); - } -#endif - return ret; + return do_getdents(arg1, arg2, arg3); #endif /* TARGET_NR_getdents */ #if defined(TARGET_NR_getdents64) && defined(__NR_getdents64) case TARGET_NR_getdents64: - { - struct linux_dirent64 *dirp; - abi_long count = arg3; - if (!(dirp = lock_user(VERIFY_WRITE, arg2, count, 0))) - return -TARGET_EFAULT; - ret = get_errno(sys_getdents64(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent64 *de; - int len = ret; - int reclen; - de = dirp; - while (len > 0) { - reclen = de->d_reclen; - if (reclen > len) - break; - de->d_reclen = tswap16(reclen); - tswap64s((uint64_t *)&de->d_ino); - tswap64s((uint64_t *)&de->d_off); - de = (struct linux_dirent64 *)((char *)de + reclen); - len -= reclen; - } - } - unlock_user(dirp, arg2, ret); - } - return ret; + return do_getdents64(arg1, arg2, arg3); #endif /* TARGET_NR_getdents64 */ #if defined(TARGET_NR__newselect) case TARGET_NR__newselect: From 540a736f54a5dffb0851f2adf455f50869b409a1 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sun, 14 Nov 2021 11:35:37 +0100 Subject: [PATCH 2/5] linux-user: Always use flexible arrays for dirent d_name MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We currently use a flexible array member for target_dirent, but use incorrectly fixed length arrays for target_dirent64, linux_dirent and linux_dirent64. This requires that we adjust the definition of the VFAT READDIR ioctls which hard-code the 256 namelen size into the ioctl constant. Signed-off-by: Richard Henderson Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20211114103539.298686-3-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier --- linux-user/syscall.c | 6 ++++-- linux-user/syscall_defs.h | 6 +++--- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index a2f605dec4..499415ad81 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -197,8 +197,10 @@ //#define DEBUG_ERESTARTSYS //#include -#define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct linux_dirent [2]) -#define VFAT_IOCTL_READDIR_SHORT _IOR('r', 2, struct linux_dirent [2]) +#define VFAT_IOCTL_READDIR_BOTH \ + _IOC(_IOC_READ, 'r', 1, (sizeof(struct linux_dirent) + 256) * 2) +#define VFAT_IOCTL_READDIR_SHORT \ + _IOC(_IOC_READ, 'r', 2, (sizeof(struct linux_dirent) + 256) * 2) #undef _syscall0 #undef _syscall1 diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h index a5ce487dcc..98b09ee6d6 100644 --- a/linux-user/syscall_defs.h +++ b/linux-user/syscall_defs.h @@ -441,7 +441,7 @@ struct target_dirent64 { int64_t d_off; unsigned short d_reclen; unsigned char d_type; - char d_name[256]; + char d_name[]; }; @@ -2714,7 +2714,7 @@ struct linux_dirent { long d_ino; unsigned long d_off; unsigned short d_reclen; - char d_name[256]; /* We must not include limits.h! */ + char d_name[]; }; struct linux_dirent64 { @@ -2722,7 +2722,7 @@ struct linux_dirent64 { int64_t d_off; unsigned short d_reclen; unsigned char d_type; - char d_name[256]; + char d_name[]; }; struct target_mq_attr { From 1962cb0029197bc0cd4bb0461171cda677e64966 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sun, 14 Nov 2021 11:35:38 +0100 Subject: [PATCH 3/5] linux-user: Fix member types of target_dirent64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The host uint64_t (etc) does not have the correct alignment constraint as the guest: use abi_* types. Signed-off-by: Richard Henderson Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20211114103539.298686-4-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier --- linux-user/syscall_defs.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h index 98b09ee6d6..41aaafbac1 100644 --- a/linux-user/syscall_defs.h +++ b/linux-user/syscall_defs.h @@ -437,9 +437,9 @@ struct target_dirent { }; struct target_dirent64 { - uint64_t d_ino; - int64_t d_off; - unsigned short d_reclen; + abi_ullong d_ino; + abi_llong d_off; + abi_ushort d_reclen; unsigned char d_type; char d_name[]; }; From aee14c77f42533f2480dfa8552f531efde6c19ee Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sun, 14 Nov 2021 11:35:39 +0100 Subject: [PATCH 4/5] linux-user: Rewrite do_getdents, do_getdents64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Always allocate host storage; this ensures that the struct is sufficiently aligned for the host. Merge the three host implementations of getdents via a few ifdefs. Utilize the same method for do_getdents64. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/704 Signed-off-by: Richard Henderson Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20211114103539.298686-5-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier --- linux-user/syscall.c | 259 ++++++++++++++++++++----------------------- 1 file changed, 121 insertions(+), 138 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 499415ad81..f1cfcc8104 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -8140,172 +8140,155 @@ static int host_to_target_cpu_mask(const unsigned long *host_mask, } #ifdef TARGET_NR_getdents -static int do_getdents(abi_long arg1, abi_long arg2, abi_long arg3) +static int do_getdents(abi_long dirfd, abi_long arg2, abi_long count) { - int ret; + g_autofree void *hdirp = NULL; + void *tdirp; + int hlen, hoff, toff; + int hreclen, treclen; + off64_t prev_diroff = 0; -#ifdef EMULATE_GETDENTS_WITH_GETDENTS -# if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64 - struct target_dirent *target_dirp; - struct linux_dirent *dirp; - abi_long count = arg3; - - dirp = g_try_malloc(count); - if (!dirp) { + hdirp = g_try_malloc(count); + if (!hdirp) { return -TARGET_ENOMEM; } - ret = get_errno(sys_getdents(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent *de; - struct target_dirent *tde; - int len = ret; - int reclen, treclen; - int count1, tnamelen; +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + hlen = sys_getdents(dirfd, hdirp, count); +#else + hlen = sys_getdents64(dirfd, hdirp, count); +#endif - count1 = 0; - de = dirp; - target_dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!target_dirp) { - return -TARGET_EFAULT; - } - tde = target_dirp; - while (len > 0) { - reclen = de->d_reclen; - tnamelen = reclen - offsetof(struct linux_dirent, d_name); - assert(tnamelen >= 0); - treclen = tnamelen + offsetof(struct target_dirent, d_name); - assert(count1 + treclen <= count); - tde->d_reclen = tswap16(treclen); - tde->d_ino = tswapal(de->d_ino); - tde->d_off = tswapal(de->d_off); - memcpy(tde->d_name, de->d_name, tnamelen); - de = (struct linux_dirent *)((char *)de + reclen); - len -= reclen; - tde = (struct target_dirent *)((char *)tde + treclen); - count1 += treclen; - } - ret = count1; - unlock_user(target_dirp, arg2, ret); + hlen = get_errno(hlen); + if (is_error(hlen)) { + return hlen; } - g_free(dirp); -# else - struct linux_dirent *dirp; - abi_long count = arg3; - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { + tdirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!tdirp) { return -TARGET_EFAULT; } - ret = get_errno(sys_getdents(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent *de; - int len = ret; - int reclen; - de = dirp; - while (len > 0) { - reclen = de->d_reclen; - if (reclen > len) { + + for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) { +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + struct linux_dirent *hde = hdirp + hoff; +#else + struct linux_dirent64 *hde = hdirp + hoff; +#endif + struct target_dirent *tde = tdirp + toff; + int namelen; + uint8_t type; + + namelen = strlen(hde->d_name); + hreclen = hde->d_reclen; + treclen = offsetof(struct target_dirent, d_name) + namelen + 2; + treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent)); + + if (toff + treclen > count) { + /* + * If the host struct is smaller than the target struct, or + * requires less alignment and thus packs into less space, + * then the host can return more entries than we can pass + * on to the guest. + */ + if (toff == 0) { + toff = -TARGET_EINVAL; /* result buffer is too small */ break; } - de->d_reclen = tswap16(reclen); - tswapls(&de->d_ino); - tswapls(&de->d_off); - de = (struct linux_dirent *)((char *)de + reclen); - len -= reclen; - } - } - unlock_user(dirp, arg2, ret); -# endif -#else - /* Implement getdents in terms of getdents64 */ - struct linux_dirent64 *dirp; - abi_long count = arg3; - - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { - return -TARGET_EFAULT; - } - ret = get_errno(sys_getdents64(arg1, dirp, count)); - if (!is_error(ret)) { - /* - * Convert the dirent64 structs to target dirent. We do this - * in-place, since we can guarantee that a target_dirent is no - * larger than a dirent64; however this means we have to be - * careful to read everything before writing in the new format. - */ - struct linux_dirent64 *de; - struct target_dirent *tde; - int len = ret; - int tlen = 0; - - de = dirp; - tde = (struct target_dirent *)dirp; - while (len > 0) { - int namelen, treclen; - int reclen = de->d_reclen; - uint64_t ino = de->d_ino; - int64_t off = de->d_off; - uint8_t type = de->d_type; - - namelen = strlen(de->d_name); - treclen = offsetof(struct target_dirent, d_name) + namelen + 2; - treclen = QEMU_ALIGN_UP(treclen, sizeof(abi_long)); - - memmove(tde->d_name, de->d_name, namelen + 1); - tde->d_ino = tswapal(ino); - tde->d_off = tswapal(off); - tde->d_reclen = tswap16(treclen); /* - * The target_dirent type is in what was formerly a padding - * byte at the end of the structure: + * Return what we have, resetting the file pointer to the + * location of the first record not returned. */ - *(((char *)tde) + treclen - 1) = type; - - de = (struct linux_dirent64 *)((char *)de + reclen); - tde = (struct target_dirent *)((char *)tde + treclen); - len -= reclen; - tlen += treclen; + lseek64(dirfd, prev_diroff, SEEK_SET); + break; } - ret = tlen; - } - unlock_user(dirp, arg2, ret); + + prev_diroff = hde->d_off; + tde->d_ino = tswapal(hde->d_ino); + tde->d_off = tswapal(hde->d_off); + tde->d_reclen = tswap16(treclen); + memcpy(tde->d_name, hde->d_name, namelen + 1); + + /* + * The getdents type is in what was formerly a padding byte at the + * end of the structure. + */ +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + type = *((uint8_t *)hde + hreclen - 1); +#else + type = hde->d_type; #endif - return ret; + *((uint8_t *)tde + treclen - 1) = type; + } + + unlock_user(tdirp, arg2, toff); + return toff; } #endif /* TARGET_NR_getdents */ #if defined(TARGET_NR_getdents64) && defined(__NR_getdents64) -static int do_getdents64(abi_long arg1, abi_long arg2, abi_long arg3) +static int do_getdents64(abi_long dirfd, abi_long arg2, abi_long count) { - struct linux_dirent64 *dirp; - abi_long count = arg3; - int ret; + g_autofree void *hdirp = NULL; + void *tdirp; + int hlen, hoff, toff; + int hreclen, treclen; + off64_t prev_diroff = 0; - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { + hdirp = g_try_malloc(count); + if (!hdirp) { + return -TARGET_ENOMEM; + } + + hlen = get_errno(sys_getdents64(dirfd, hdirp, count)); + if (is_error(hlen)) { + return hlen; + } + + tdirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!tdirp) { return -TARGET_EFAULT; } - ret = get_errno(sys_getdents64(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent64 *de; - int len = ret; - int reclen; - de = dirp; - while (len > 0) { - reclen = de->d_reclen; - if (reclen > len) { + + for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) { + struct linux_dirent64 *hde = hdirp + hoff; + struct target_dirent64 *tde = tdirp + toff; + int namelen; + + namelen = strlen(hde->d_name) + 1; + hreclen = hde->d_reclen; + treclen = offsetof(struct target_dirent64, d_name) + namelen; + treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent64)); + + if (toff + treclen > count) { + /* + * If the host struct is smaller than the target struct, or + * requires less alignment and thus packs into less space, + * then the host can return more entries than we can pass + * on to the guest. + */ + if (toff == 0) { + toff = -TARGET_EINVAL; /* result buffer is too small */ break; } - de->d_reclen = tswap16(reclen); - tswap64s((uint64_t *)&de->d_ino); - tswap64s((uint64_t *)&de->d_off); - de = (struct linux_dirent64 *)((char *)de + reclen); - len -= reclen; + /* + * Return what we have, resetting the file pointer to the + * location of the first record not returned. + */ + lseek64(dirfd, prev_diroff, SEEK_SET); + break; } + + prev_diroff = hde->d_off; + tde->d_ino = tswap64(hde->d_ino); + tde->d_off = tswap64(hde->d_off); + tde->d_reclen = tswap16(treclen); + tde->d_type = hde->d_type; + memcpy(tde->d_name, hde->d_name, namelen); } - unlock_user(dirp, arg2, ret); - return ret; + + unlock_user(tdirp, arg2, toff); + return toff; } #endif /* TARGET_NR_getdents64 */ From 802ae45e94151a6d3ee20eadcb865cf6c875df34 Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Sun, 21 Nov 2021 16:17:11 +0100 Subject: [PATCH 5/5] linux-user: fix Coverity CID 1464101 target_mmap() can fail and return -1, but we don't check for that and instead assume it's always valid. Fixes: db2af69d6ba8 ("linux-user: Add infrastructure for a signal trampoline page") Cc: richard.henderson@linaro.org Reported-by: Peter Maydell Signed-off-by: Laurent Vivier Reviewed-by: Richard Henderson Message-Id: <20211121151711.331653-1-laurent@vivier.eu> Signed-off-by: Laurent Vivier --- linux-user/elfload.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 5da8c02d08..767f54c76d 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -3254,9 +3254,13 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info) * Otherwise, allocate a private page to hold them. */ if (TARGET_ARCH_HAS_SIGTRAMP_PAGE) { - abi_ulong tramp_page = target_mmap(0, TARGET_PAGE_SIZE, - PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANON, -1, 0); + abi_long tramp_page = target_mmap(0, TARGET_PAGE_SIZE, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANON, -1, 0); + if (tramp_page == -1) { + return -errno; + } + setup_sigtramp(tramp_page); target_mprotect(tramp_page, TARGET_PAGE_SIZE, PROT_READ | PROT_EXEC); }