[PATCH net-next v4 03/17] net: pktgen: fix hex32_arg parsing for short reads

Peter Seiderer
2025-02-05T13:12:03Z

Fix hex32_arg parsing for short reads (here 7 hex digits instead of the
expected 8), shift result only on successful input parsing.

- before the patch

$ echo "mpls 0000123" > /proc/net/pktgen/lo\@0
$ grep mpls /proc/net/pktgen/lo\@0
mpls: 00001230
Result: OK: mpls=00001230

- with patch applied

$ echo "mpls 0000123" > /proc/net/pktgen/lo\@0
$ grep mpls /proc/net/pktgen/lo\@0
mpls: 00000123
Result: OK: mpls=00000123

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Reviewed-by: Simon Horman <horms@kernel.org>
---
Changes v3 -> v4
- add rev-by Simon Horman

Changes v2 -> v3:
- no changes

Changes v1 -> v2:
- new patch
---
net/core/pktgen.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 4f8ec6c9bed4..28dbbf70e142 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -753,14 +753,15 @@ static int hex32_arg(const char __user *user_buffer, unsigned long maxlen,
for (; i < maxlen; i++) {
int value;
char c;
- *num <<= 4;
if (get_user(c, &user_buffer[i]))
return -EFAULT;
value = hex_to_bin(c);
- if (value >= 0)
+ if (value >= 0) {
+ *num <<= 4;
*num |= value;
- else
+ } else {
break;
+ }
}
return i;
}
--
2.48.1