reiserfs: fix broken xattr handling (heap corruption, bad retval)
This fixes the following issues:
- When a buffer size is supplied to reiserfs_listxattr() such that each
individual name fits, but the concatenation of all names doesn't fit,
reiserfs_listxattr() overflows the supplied buffer. This leads to a
kernel heap overflow (verified using KASAN) followed by an out-of-bounds
usercopy and is therefore a security bug.
- When a buffer size is supplied to reiserfs_listxattr() such that a
name doesn't fit, -ERANGE should be returned. But reiserfs instead just
truncates the list of names; I have verified that if the only xattr on a
file has a longer name than the supplied buffer length, listxattr()
incorrectly returns zero.
With my patch applied, -ERANGE is returned in both cases and the memory
corruption doesn't happen anymore.
Credit for making me clean this code up a bit goes to Al Viro, who pointed
out that the ->actor calling convention is suboptimal and should be
changed.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 48b32a3553a5 ("reiserfs: use generic xattr handlers")
Signed-off-by: Jann Horn <[email protected]>
Acked-by: Jeff Mahoney <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Al Viro <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
1 file changed
