[PATCH v2] objtool: check: give big enough buffer for pv_ops

From: Sergei Trofimovich
Date: Thu Jan 20 2022 - 18:37:56 EST


On gcc-12 build fails flagging possible buffer overflow:

check.c: In function 'validate_call':
check.c:2865:58: error: '%d' directive output may be truncated writing between 1 and 10 bytes into a region of size 9 [-Werror=format-truncation=]
2865 | snprintf(pvname, sizeof(pvname), "pv_ops[%d]", idx);
| ^~

I think it's a valid warning:

static char pvname[16];
int idx;
...
idx = (rel->addend / sizeof(void *));
snprintf(pvname, sizeof(pvname), "pv_ops[%d]", idx);

we have only 7 chars for %d while it could take up to 9.

CC: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Sergei Trofimovich <slyich@xxxxxxxxx>
---
Change since v1: added missing S-O-B.
tools/objtool/check.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index c2d2ab9a2861..f5bed94e4558 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2854,7 +2854,7 @@ static inline bool func_uaccess_safe(struct symbol *func)

static inline const char *call_dest_name(struct instruction *insn)
{
- static char pvname[16];
+ static char pvname[32];
struct reloc *rel;
int idx;

--
2.34.1