[34-longterm 113/179] si4713-i2c: avoid potential buffer overflow on si4713

[Paul Gortmaker]

From: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit dc6b845044ccb7e9e6f3b7e71bd179b3cf0223b6 upstream.

While compiling it with Fedora 15, I noticed this issue:

  inlined from âsi4713_write_econtrol_stringâ at drivers/media/radio/si4713-i2c.c:1065:24:
  arch/x86/include/asm/uaccess_32.h:211:26: error: call to âcopy_from_user_overflowâ declared with attribute error: copy_from_user() buffer size is not provably correct

Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx>
Acked-by: Eduardo Valentin <edubezval@xxxxxxxxx>
Reviewed-by: Eugene Teo <eugeneteo@xxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 drivers/media/radio/si4713-i2c.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/radio/si4713-i2c.c b/drivers/media/radio/si4713-i2c.c
index ab63dd5..6ce2fb1 100644
--- a/drivers/media/radio/si4713-i2c.c
+++ b/drivers/media/radio/si4713-i2c.c
@@ -1004,7 +1004,7 @@ static int si4713_write_econtrol_string(struct si4713_device *sdev,
 		char ps_name[MAX_RDS_PS_NAME + 1];
 
 		len = control->size - 1;
-		if (len > MAX_RDS_PS_NAME) {
+		if (len < 0 || len > MAX_RDS_PS_NAME) {
 			rval = -ERANGE;
 			goto exit;
 		}
@@ -1026,7 +1026,7 @@ static int si4713_write_econtrol_string(struct si4713_device *sdev,
 		char radio_text[MAX_RDS_RADIO_TEXT + 1];
 
 		len = control->size - 1;
-		if (len > MAX_RDS_RADIO_TEXT) {
+		if (len < 0 || len > MAX_RDS_RADIO_TEXT) {
 			rval = -ERANGE;
 			goto exit;
 		}
-- 
1.7.9.6

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