A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-28 02:32:09 -04:00
Code Issues Projects Releases Packages Wiki Activity

lib: Fix strnlen_user() to not touch memory after specified maximum

Browse source 
If the specified maximum length of the string is a multiple of unsigned
long, we would load one long behind the specified maximum.  If that
happens to be in a next page, we can hit a page fault although we were
not expected to.

Fix the off-by-one bug in the test whether we are at the end of the
specified range.

Signed-off-by: Jan Kara <[email protected]>
Cc: [email protected]
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Jan Kara 2015-06-02 17:10:28 +02:00 • committed by Linus Torvalds
commit f18c34e483
1 changed files with 2 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

3
lib/strnlen_user.c
View file

@ -57,7 +57,8 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
return res + find_zero(data) + 1 - align;
}
res += sizeof(unsigned long);
if (unlikely(max < sizeof(unsigned long)))
/* We already handled 'unsigned long' bytes. Did we do it all ? */
if (unlikely(max <= sizeof(unsigned long)))
break;
max -= sizeof(unsigned long);
if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))