From 1fcbf053e55e961112f237dc690129f0858156f1 Mon Sep 17 00:00:00 2001 From: Kyle McMartin Date: Tue, 7 Feb 2006 12:58:47 -0800 Subject: [PATCH] [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 Signed-off-by: Linus Torvalds --- arch/parisc/hpux/sys_hpux.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/parisc/hpux/sys_hpux.c b/arch/parisc/hpux/sys_hpux.c index 29b4d61898..05273ccced 100644 --- a/arch/parisc/hpux/sys_hpux.c +++ b/arch/parisc/hpux/sys_hpux.c @@ -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; -- 2.39.5