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[PATCH] sys_hpux: fix strlen_user() race 

Userspace can alter the string after the kernel has run strlen_user().

Also: the strlen_user() return value includes the \0, so fix that.

Also: handle EFAULT from strlen_user().

It's unlikely anyone is using this code.  Very, very unlikely.  If I
remember correctly, CONFIG_HPUX turns this code on, but one would actually
need CONFIG_BINFMT_SOM to load a binary that could cause a problem, and
BINFMT_SOM has had an #error in it for quite some time.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Kyle McMartin 2006-02-07 12:58:47 -08:00 committed by Linus Torvalds
parent b5173119ff
commit 1fcbf053e5
1 changed files with 7 additions and 3 deletions
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10
arch/parisc/hpux/sys_hpux.c
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@ -468,19 +468,23 @@ int hpux_sysfs(int opcode, unsigned long arg1, unsigned long arg2)
if ( opcode == 1 ) { /* GETFSIND */
len = strlen_user((char *)arg1);
printk(KERN_DEBUG "len of arg1 = %d\n", len);
fsname = (char *) kmalloc(len+1, GFP_KERNEL);
if (len == 0)
return 0;
fsname = (char *) kmalloc(len, GFP_KERNEL);
if ( !fsname ) {
printk(KERN_DEBUG "failed to kmalloc fsname\n");
return 0;
}
if ( copy_from_user(fsname, (char *)arg1, len+1) ) {
if ( copy_from_user(fsname, (char *)arg1, len) ) {
printk(KERN_DEBUG "failed to copy_from_user fsname\n");
kfree(fsname);
return 0;
}
/* String could be altered by userspace after strlen_user() */
fsname[len] = '\0';
printk(KERN_DEBUG "that is '%s' as (char *)\n", fsname);
if ( !strcmp(fsname, "hfs") ) {
fstype = 0;