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compat getdents64: Use correct offset for retry [BZ #23972]
d_off is the offset of the *next* entry, not the offset of the current entry.
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@ -1,3 +1,13 @@
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2018-12-10 Florian Weimer <fweimer@redhat.com>
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[BZ #23972]
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* sysdeps/unix/sysv/linux/getdents64.c (handle_overflow): Check
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offset instead of count for clarity. Fix typo in comment.
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(__old_getdents64): Keep track of previous offset. Use it to call
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handle_overflow.
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* sysdeps/unix/sysv/linux/tst-readdir64-compat.c (do_test): Check
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that d_off is never zero.
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2018-12-10 Andreas Schwab <schwab@suse.de>
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* sysdeps/unix/sysv/linux/powerpc/powerpc64/*-le.abilist: Move to
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@ -41,14 +41,14 @@ handle_overflow (int fd, __off64_t offset, ssize_t count)
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{
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/* If this is the first entry in the buffer, we can report the
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error. */
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if (count == 0)
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if (offset == 0)
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{
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__set_errno (EOVERFLOW);
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return -1;
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}
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/* Otherwise, seek to the overflowing entry, so that the next call
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will report the error, and return the data read so far.. */
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will report the error, and return the data read so far. */
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if (__lseek64 (fd, offset, SEEK_SET) != 0)
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return -1;
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return count;
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@ -70,6 +70,15 @@ __old_getdents64 (int fd, char *buf, size_t nbytes)
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ssize_t retval = INLINE_SYSCALL_CALL (getdents64, fd, buf, nbytes);
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if (retval > 0)
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{
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/* This is the marker for the first entry. Offset 0 is reserved
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for the first entry (see rewinddir). Here, we use it as a
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marker for the first entry in the buffer. We never actually
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seek to offset 0 because handle_overflow reports the error
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directly, so it does not matter that the offset is incorrect
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if entries have been read from the descriptor before (so that
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the descriptor is not actually at offset 0). */
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__off64_t previous_offset = 0;
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char *p = buf;
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char *end = buf + retval;
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while (p < end)
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@ -84,7 +93,7 @@ __old_getdents64 (int fd, char *buf, size_t nbytes)
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/* Check for ino_t overflow. */
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if (__glibc_unlikely (ino != source->d_ino))
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return handle_overflow (fd, offset, p - buf);
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return handle_overflow (fd, previous_offset, p - buf);
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/* Convert to the target layout. Use a separate struct and
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memcpy to side-step aliasing issues. */
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@ -107,6 +116,7 @@ __old_getdents64 (int fd, char *buf, size_t nbytes)
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reclen - offsetof (struct dirent64, d_name));
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p += reclen;
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previous_offset = offset;
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}
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}
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return retval;
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@ -88,6 +88,10 @@ do_test (void)
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else
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TEST_VERIFY_EXIT (entry_test != NULL);
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/* d_off is never zero because it is the offset of the next
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entry (not the current entry). */
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TEST_VERIFY (entry_reference->d_off > 0);
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/* Check that the entries are the same. */
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TEST_COMPARE_BLOB (entry_reference->d_name,
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strlen (entry_reference->d_name),
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