From: Nandakumar Edamana nandakumar@nandakumar.co.in
[ Upstream commit 236d3910117e9f97ebf75e511d8bcc950f1a4e5f ]
In `set_kcfg_value_str`, an untrusted string is accessed with the assumption that it will be at least two characters long due to the presence of checks for opening and closing quotes. But the check for the closing quote (value[len - 1] != '"') misses the fact that it could be checking the opening quote itself in case of an invalid input that consists of just the opening quote.
This commit adds an explicit check to make sure the string is at least two characters long.
Signed-off-by: Nandakumar Edamana nandakumar@nandakumar.co.in Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20250221210110.3182084-1-nandakumar@nandakumar.c... Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 294fdba9c76f7..40e0d84e3d8ed 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1567,7 +1567,7 @@ static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val, }
len = strlen(value); - if (value[len - 1] != '"') { + if (len < 2 || value[len - 1] != '"') { pr_warn("extern (kcfg) '%s': invalid string config '%s'\n", ext->name, value); return -EINVAL;