ext4: force revalidation of directory pointer after seekdir(2)

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commit e40ff21389 upstream.

A malicious user could force the directory pointer to be in an invalid
spot by using seekdir(2).  Use the mechanism we already have to notice
if the directory has changed since the last time we called
ext4_readdir() to force a revalidation of the pointer.

Reported-by: syzbot+1236ce66f79263e8a862@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.16: open-code inode_peek_iversion()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

...

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Theodore Ts'o 2018-04-01 23:21:03 -04:00 • committed by Ben Hutchings

parent ac73160915

commit e800c3836e

1 changed files with 5 additions and 3 deletions

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fs/ext4/dir.c

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