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apparmor: increase left match history buffer size 

There have been cases reported where a history buffer size of 8 was
not enough to resolve conflict overlaps. Increase the buffer to and
get rid of the size element which is currently just storing the
constant WB_HISTORY_SIZE.

Signed-off-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
John Johansen 2019-05-31 06:54:54 -07:00
parent 8ac2ca328e
commit 136db99485
2 changed files with 4 additions and 5 deletions
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3
security/apparmor/include/match.h
View File

@ -138,7 +138,7 @@ unsigned int aa_dfa_matchn_until(struct aa_dfa *dfa, unsigned int start,
void aa_dfa_free_kref(struct kref *kref); void aa_dfa_free_kref(struct kref *kref);
#define WB_HISTORY_SIZE 8 #define WB_HISTORY_SIZE 24
struct match_workbuf { struct match_workbuf {
unsigned int count; unsigned int count;
unsigned int pos; unsigned int pos;
@ -151,7 +151,6 @@ struct match_workbuf N = { \
.count = 0, \ .count = 0, \
.pos = 0, \ .pos = 0, \
.len = 0, \ .len = 0, \
.size = WB_HISTORY_SIZE, \
} }
unsigned int aa_dfa_leftmatch(struct aa_dfa *dfa, unsigned int start, unsigned int aa_dfa_leftmatch(struct aa_dfa *dfa, unsigned int start,

6
security/apparmor/match.c
View File

@ -620,8 +620,8 @@ unsigned int aa_dfa_matchn_until(struct aa_dfa *dfa, unsigned int start,
#define inc_wb_pos(wb) \ #define inc_wb_pos(wb) \
do { \ do { \
wb->pos = (wb->pos + 1) & (wb->size - 1); \ wb->pos = (wb->pos + 1) & (WB_HISTORY_SIZE - 1); \
wb->len = (wb->len + 1) & (wb->size - 1); \ wb->len = (wb->len + 1) & (WB_HISTORY_SIZE - 1); \
} while (0) } while (0)
/* For DFAs that don't support extended tagging of states */ /* For DFAs that don't support extended tagging of states */
@ -640,7 +640,7 @@ static bool is_loop(struct match_workbuf *wb, unsigned int state,
return true; return true;
} }
if (pos == 0) if (pos == 0)
pos = wb->size; pos = WB_HISTORY_SIZE;
pos--; pos--;
} }