From 8244369e8db982384a834622749601467a06b56f Mon Sep 17 00:00:00 2001 From: Zhang Enpei Date: Wed, 2 Jul 2025 12:17:23 +0800 Subject: [PATCH] of: module: add buffer overflow check in of_modalias() commit 0b0d5701a8bf02f8fee037e81aacf6746558bfd6 upstream. [ Upstream commit cf7385cb26ac4f0ee6c7385960525ad534323252 ] In of_modalias(), if the buffer happens to be too small even for the 1st snprintf() call, the len parameter will become negative and str parameter (if not NULL initially) will point beyond the buffer's end. Add the buffer overflow check after the 1st snprintf() call and fix such check after the strlen() call (accounting for the terminating NUL char). Fixes: bc575064d688 ("of/device: use of_property_for_each_string to parse compatible strings") Signed-off-by: Sergey Shtylyov Link: https://lore.kernel.org/r/bbfc6be0-c687-62b6-d015-5141b93f313e@omp.ru Signed-off-by: Rob Herring Signed-off-by: Sasha Levin Fixes: CVE-2024-38541 Signed-off-by: Enpei Zhang Signed-off-by: Wenya Zhang Reviewed-by: Xuexin Jiang --- drivers/of/module.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/of/module.c b/drivers/of/module.c index 0e8aa974f0f2..6c2c3e91f7ed 100644 --- a/drivers/of/module.c +++ b/drivers/of/module.c @@ -21,14 +21,15 @@ ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len) csize = snprintf(str, len, "of:N%pOFn%c%s", np, 'T', of_node_get_device_type(np)); tsize = csize; + if (csize >= len) + csize = len > 0 ? len - 1 : 0; len -= csize; - if (str) - str += csize; + str += csize; of_property_for_each_string(np, "compatible", p, compat) { csize = strlen(compat) + 1; tsize += csize; - if (csize > len) + if (csize >= len) continue; csize = snprintf(str, len, "C%s", compat); -- Gitee