diff options
| author | Servaas Vandenberghe <vdb@picaros.org> | 2011-08-31 07:06:49 +0200 |
|---|---|---|
| committer | Peter Hutterer <peter.hutterer@who-t.net> | 2011-10-31 09:39:04 +1000 |
| commit | 820d9040f50a8440741b3aefbc069a3ad81e824e (patch) | |
| tree | 2ee7a91f1bd55b6b163f76b61ee2fe526357585d /hw/xfree86/parser | |
| parent | 63e87b8639eb8e0b4e32e5d3a09099d31a03bbcd (diff) | |
xfree86: fix potential buffer overflow
The patch below fixes a potential buffer overflow in xf86addComment().
This occurs if curlen > 0 && eol_seen == 0 && iscomment == 0 , as
follows from the code:
char *xf86addComment(char *cur, char *add)
<...>
len = strlen(add);
endnewline = add[len - 1] == '\n';
len += 1 + iscomment + (!hasnewline) + (!endnewline) + eol_seen;
if ((str = realloc(cur, len + curlen)) == NULL)
return cur;
cur = str;
if (eol_seen || (curlen && !hasnewline))
cur[curlen++] = '\n';
if (!iscomment)
cur[curlen++] = '#';
strcpy(cur + curlen, add);
if (!endnewline)
strcat(cur, "\n");
Signed-off-by: Servaas Vandenberghe <vdb@picaros.org>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
[whot: added buffer overflow test case]
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Diffstat (limited to 'hw/xfree86/parser')
| -rw-r--r-- | hw/xfree86/parser/scan.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/hw/xfree86/parser/scan.c b/hw/xfree86/parser/scan.c index 1cff3bc5c..99b325717 100644 --- a/hw/xfree86/parser/scan.c +++ b/hw/xfree86/parser/scan.c @@ -1093,7 +1093,7 @@ char * xf86addComment(char *cur, char *add) { char *str; - int len, curlen, iscomment, hasnewline = 0, endnewline; + int len, curlen, iscomment, hasnewline = 0, insnewline, endnewline; if (add == NULL || add[0] == '\0') return cur; @@ -1118,14 +1118,23 @@ xf86addComment(char *cur, char *add) len = strlen(add); endnewline = add[len - 1] == '\n'; - len += 1 + iscomment + (!hasnewline) + (!endnewline) + eol_seen; - if ((str = realloc(cur, len + curlen)) == NULL) + insnewline = eol_seen || (curlen && !hasnewline); + if (insnewline) + len++; + if (!iscomment) + len++; + if (!endnewline) + len++; + + /* Allocate + 1 char for '\0' terminator. */ + str = realloc(cur, curlen + len + 1); + if (!str) return cur; cur = str; - if (eol_seen || (curlen && !hasnewline)) + if (insnewline) cur[curlen++] = '\n'; if (!iscomment) cur[curlen++] = '#'; |