[PATCH] [17/50] si4713-i2c: avoid potential buffer overflow on si4713

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>

[ upstream commit dc6b845044ccb7e9e6f3b7e71bd179b3cf0223b6 ]
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While compiling it with Fedora 15, I noticed this issue:

  inlined from â??si4713_write_econtrol_stringâ?? at drivers/media/radio/si4713-i2c.c:1065:24:
  arch/x86/include/asm/uaccess_32.h:211:26: error: call to â??copy_from_user_overflowâ?? declared with attribute error: copy_from_user() buffer size is not provably correct

Cc: stable@xxxxxxxxxx
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: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Index: linux-2.6.35.y/drivers/media/radio/si4713-i2c.c
===================================================================
--- linux-2.6.35.y.orig/drivers/media/radio/si4713-i2c.c
+++ linux-2.6.35.y/drivers/media/radio/si4713-i2c.c
@@ -1004,7 +1004,7 @@ static int si4713_write_econtrol_string(
 		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(
 		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;
 		}
--
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