2016-12-08 04:16:03

by Maninder Singh

Subject: [PATCH v3] mach-omap2: fixing wrong strcat for Non-NULL terminated string

Issue caught with static analysis tool:
"Dangerous usage of 'name' (strncpy doesn't always 0-terminate it)"

Use strlcpy _includes_ the NUL terminator, and strlcat() which ensures
that it won't overflow the buffer.

Reported-by: Maninder Singh <[email protected]>
Signed-off-by: Vaneet Narang <[email protected]>
CC: Russell King <[email protected]>
---
v1 -> v2: changed strncpy to strlcpy
v2 -> v3: use of strlcat as suggested by Russell to
make change clearer and simpler.

arch/arm/mach-omap2/omap_hwmod.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 759e1d4..e8b9887 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -741,14 +741,14 @@ static int _init_main_clk(struct omap_hwmod *oh)
int ret = 0;
char name[MOD_CLK_MAX_NAME_LEN];
struct clk *clk;
+ static const char modck[] = "_mod_ck";

- /* +7 magic comes from '_mod_ck' suffix */
- if (strlen(oh->name) + 7 > MOD_CLK_MAX_NAME_LEN)
+ if (strlen(oh->name) >= MOD_CLK_MAX_NAME_LEN - strlen(modck))
pr_warn("%s: warning: cropping name for %s\n", __func__,
oh->name);

- strncpy(name, oh->name, MOD_CLK_MAX_NAME_LEN - 7);
- strcat(name, "_mod_ck");
+ strlcpy(name, oh->name, MOD_CLK_MAX_NAME_LEN - strlen(modck));
+ strlcat(name, modck, MOD_CLK_MAX_NAME_LEN);

clk = clk_get(NULL, name);
if (!IS_ERR(clk)) {
--
1.9.1

2016-12-27 17:40:31

by Tony Lindgren

Subject: Re: [PATCH v3] mach-omap2: fixing wrong strcat for Non-NULL terminated string

* Maninder Singh <[email protected]> [161207 20:16]:
> Issue caught with static analysis tool:
> "Dangerous usage of 'name' (strncpy doesn't always 0-terminate it)"
>
> Use strlcpy _includes_ the NUL terminator, and strlcat() which ensures
> that it won't overflow the buffer.

Applying into omap-for-v4.10/fixes thanks.

Tony