From 54d11736ec3179954b6cdea4b4e1136d6bb39f39 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 8 Nov 2017 13:08:39 +0100 Subject: platform/x86: dell-smbios: fix string overflow The new sysfs code overwrites two fixed-length character arrays that are each one byte shorter than they need to be, to hold the trailing \0: drivers/platform/x86/dell-smbios.c: In function 'build_tokens_sysfs': drivers/platform/x86/dell-smbios.c:494:42: error: 'sprintf' writing a terminating nul past the end of the destination [-Werror=format-overflow=] sprintf(buffer_location, "%04x_location", drivers/platform/x86/dell-smbios.c:494:3: note: 'sprintf' output 14 bytes into a destination of size 13 drivers/platform/x86/dell-smbios.c:506:36: error: 'sprintf' writing a terminating nul past the end of the destination [-Werror=format-overflow=] sprintf(buffer_value, "%04x_value", drivers/platform/x86/dell-smbios.c:506:3: note: 'sprintf' output 11 bytes into a destination of size 10 This changes it to just use kasprintf(), which always gets it right. Discovered with gcc-7.1.1 with the following commit reverted: bd664f6b3e disable new gcc-7.1.1 warnings for now Fixes: 33b9ca1e53b4 ("platform/x86: dell-smbios: Add a sysfs interface for SMBIOS tokens") Signed-off-by: Arnd Bergmann Acked-by: Mario Limonciello [dvhart: add subject prefix and reproducer details for context] Signed-off-by: Darren Hart (VMware) --- drivers/platform/x86/dell-smbios.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'drivers/platform') diff --git a/drivers/platform/x86/dell-smbios.c b/drivers/platform/x86/dell-smbios.c index d99edd803c19..6a60db515bda 100644 --- a/drivers/platform/x86/dell-smbios.c +++ b/drivers/platform/x86/dell-smbios.c @@ -463,8 +463,6 @@ static struct platform_driver platform_driver = { static int build_tokens_sysfs(struct platform_device *dev) { - char buffer_location[13]; - char buffer_value[10]; char *location_name; char *value_name; size_t size; @@ -491,9 +489,8 @@ static int build_tokens_sysfs(struct platform_device *dev) if (da_tokens[i].tokenID == 0) continue; /* add location */ - sprintf(buffer_location, "%04x_location", - da_tokens[i].tokenID); - location_name = kstrdup(buffer_location, GFP_KERNEL); + location_name = kasprintf(GFP_KERNEL, "%04x_location", + da_tokens[i].tokenID); if (location_name == NULL) goto out_unwind_strings; sysfs_attr_init(&token_location_attrs[i].attr); @@ -503,9 +500,8 @@ static int build_tokens_sysfs(struct platform_device *dev) token_attrs[j++] = &token_location_attrs[i].attr; /* add value */ - sprintf(buffer_value, "%04x_value", - da_tokens[i].tokenID); - value_name = kstrdup(buffer_value, GFP_KERNEL); + value_name = kasprintf(GFP_KERNEL, "%04x_value", + da_tokens[i].tokenID); if (value_name == NULL) goto loop_fail_create_value; sysfs_attr_init(&token_value_attrs[i].attr); -- cgit v1.2.3