path: root/lib/parser.c
diff options
authorAlex Elder <>2012-10-04 17:13:16 -0700
committerLinus Torvalds <>2012-10-06 03:04:56 +0900
commit77dd3b0bd17a0849b2f98b915ce3fc9247db1013 (patch)
treea6ff9f120d790b5559e3f91cf9849e9f84ee1e65 /lib/parser.c
parent125c4c706b680c7831f0966ff873c1ad0354ec25 (diff)
lib/parser.c: avoid overflow in match_number()
The result of converting an integer value to another signed integer type that's unable to represent the original value is implementation defined. (See notes in section of the C standard.) In match_number(), the result of simple_strtol() (which returns type long) is assigned to a value of type int. Instead, handle the result of simple_strtol() in a well-defined way, and return -ERANGE if the result won't fit in the int variable used to hold the parsed result. No current callers pay attention to the particular error value returned, so this additional return code shouldn't do any harm. [ coding-style tweaks] Signed-off-by: Alex Elder <> Cc: Randy Dunlap <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'lib/parser.c')
1 files changed, 8 insertions, 2 deletions
diff --git a/lib/parser.c b/lib/parser.c
index c43410084838..52cfa69f73df 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -122,13 +122,14 @@ int match_token(char *s, const match_table_t table, substring_t args[])
* Description: Given a &substring_t and a base, attempts to parse the substring
* as a number in that base. On success, sets @result to the integer represented
- * by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure.
+ * by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
static int match_number(substring_t *s, int *result, int base)
char *endp;
char *buf;
int ret;
+ long val;
size_t len = s->to - s->from;
buf = kmalloc(len + 1, GFP_KERNEL);
@@ -136,10 +137,15 @@ static int match_number(substring_t *s, int *result, int base)
return -ENOMEM;
memcpy(buf, s->from, len);
buf[len] = '\0';
- *result = simple_strtol(buf, &endp, base);
ret = 0;
+ val = simple_strtol(buf, &endp, base);
if (endp == buf)
ret = -EINVAL;
+ else if (val < (long)INT_MIN || val > (long)INT_MAX)
+ ret = -ERANGE;
+ else
+ *result = (int) val;
return ret;