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Linux: Use readdir64_r for compat __old_readdir64_r (bug 32128)

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It is not necessary to do the conversion at the getdents64
layer for readdir64_r.  Doing it piecewise for readdir64
is slightly simpler and allows deleting __old_getdents64.

This fixes bug 32128 because readdir64_r handles the length
check correctly.

Reviewed-by: DJ Delorie <dj@redhat.com>
This commit is contained in:
Florian Weimer
2024-09-21 19:32:34 +02:00
parent 4c09aa31b1
commit e92718552e
4 changed files with 72 additions and 217 deletions
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98
sysdeps/unix/sysv/linux/readdir64_r.c
View File

@@ -135,91 +135,37 @@ attribute_compat_text_section
__old_readdir64_r (DIR *dirp, struct __old_dirent64 *entry,
struct __old_dirent64 **result)
{
struct __old_dirent64 *dp;
size_t reclen;
const int saved_errno = errno;
int ret;
__libc_lock_lock (dirp->lock);
do
while (1)
{
if (dirp->offset >= dirp->size)
struct dirent64 new_entry;
struct dirent64 *newp;
int ret = __readdir64_r (dirp, &new_entry, &newp);
if (ret != 0)
return ret;
else if (newp == NULL)
{
/* We've emptied out our buffer. Refill it. */
size_t maxread = dirp->allocation;
ssize_t bytes;
maxread = dirp->allocation;
bytes = __old_getdents64 (dirp->fd, dirp->data, maxread);
if (bytes <= 0)
{
/* On some systems getdents fails with ENOENT when the
open directory has been rmdir'd already. POSIX.1
requires that we treat this condition like normal EOF. */
if (bytes < 0 && errno == ENOENT)
{
bytes = 0;
__set_errno (saved_errno);
}
if (bytes < 0)
dirp->errcode = errno;
dp = NULL;
break;
}
dirp->size = (size_t) bytes;
/* Reset the offset into the buffer. */
dirp->offset = 0;
*result = NULL;
return 0;
}
dp = (struct __old_dirent64 *) &dirp->data[dirp->offset];
reclen = dp->d_reclen;
dirp->offset += reclen;
dirp->filepos = dp->d_off;
if (reclen > offsetof (struct __old_dirent64, d_name) + NAME_MAX + 1)
else
{
/* The record is very long. It could still fit into the
caller-supplied buffer if we can skip padding at the
end. */
size_t namelen = _D_EXACT_NAMLEN (dp);
if (namelen <= NAME_MAX)
reclen = offsetof (struct __old_dirent64, d_name) + namelen + 1;
else
entry->d_ino = newp->d_ino;
if (entry->d_ino != newp->d_ino)
{
/* The name is too long. Ignore this file. */
dirp->errcode = ENAMETOOLONG;
dp->d_ino = 0;
dirp->errcode = EOVERFLOW;
continue;
}
size_t namelen = strlen (newp->d_name);
entry->d_off = newp->d_off;
entry->d_reclen = (offsetof (struct __old_dirent64, d_name)
+ namelen + 1);
entry->d_type = newp->d_type;
memcpy (entry->d_name, newp->d_name, namelen + 1);
*result = entry;
return 0;
}
/* Skip deleted and ignored files. */
}
while (dp->d_ino == 0);
if (dp != NULL)
{
*result = memcpy (entry, dp, reclen);
entry->d_reclen = reclen;
ret = 0;
}
else
{
*result = NULL;
ret = dirp->errcode;
}
__libc_lock_unlock (dirp->lock);
return ret;
}
compat_symbol (libc, __old_readdir64_r, readdir64_r, GLIBC_2_1);