commit 6b4dbcd86a9d464057fcc7abe4d0574093071fcc
author Michael Buesch <mb@bu3sch.de> Mon Jul 20 22:58:44 2009 +0000
committer Helge Deller <deller@gmx.de> Sun Aug 02 12:35:52 2009 +0200
tree dd1dc64562db85a382a6118335821c311809cac3
parent 450d6e306b4717bfae11218a02648509baf04ce1

parisc: isa-eeprom - Fix loff_t usage

loff_t is a signed type. If userspace passes a negative ppos, the "count"
range check is weakened. "count"s bigger than HPEE_MAX_LENGTH will pass the check.
Also, if ppos is negative, the readb(eisa_eeprom_addr + *ppos) will poke in random
memory.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: stable@kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/parisc/eisa_eeprom.c

diff --git a/drivers/parisc/eisa_eeprom.c b/drivers/parisc/eisa_eeprom.c
index 685d94e..8c0b26e9 100644
--- a/drivers/parisc/eisa_eeprom.c
+++ b/drivers/parisc/eisa_eeprom.c
@@ -55,7 +55,7 @@
 	ssize_t ret;
 	int i;
 	
-	if (*ppos >= HPEE_MAX_LENGTH)
+	if (*ppos < 0 || *ppos >= HPEE_MAX_LENGTH)
 		return 0;
 	
 	count = *ppos + count < HPEE_MAX_LENGTH ? count : HPEE_MAX_LENGTH - *ppos;