GIT: unionfs2-2.6.27.y: parisc: isa-eeprom - Fix loff_t usage

[Erez Zadok]

commit 1f059b24d2a9f0f15766d0f77acaaa3c8a163a3a
Author: Michael Buesch <mb at bu3sch.de>
Date:   Mon Jul 20 22:58:44 2009 +0000

    parisc: isa-eeprom - Fix loff_t usage
    
    commit 6b4dbcd86a9d464057fcc7abe4d0574093071fcc upstream.
    
    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 at bu3sch.de>
    Signed-off-by: Helge Deller <deller at gmx.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>

diff --git a/drivers/parisc/eisa_eeprom.c b/drivers/parisc/eisa_eeprom.c
index 5ac2079..7eee236 100644
--- a/drivers/parisc/eisa_eeprom.c
+++ b/drivers/parisc/eisa_eeprom.c
@@ -55,7 +55,7 @@ static ssize_t eisa_eeprom_read(struct file * file,
 	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;