From c25a785d6647984505fa165b5cd84cfc9a95970b Mon Sep 17 00:00:00 2001 From: Dan Rosenberg Date: Fri, 20 Jan 2012 14:34:27 -0800 Subject: [PATCH] score: fix off-by-one index into syscall table If the provided system call number is equal to __NR_syscalls, the current check will pass and a function pointer just after the system call table may be called, since sys_call_table is an array with total size __NR_syscalls. Whether or not this is a security bug depends on what the compiler puts immediately after the system call table. It's likely that this won't do anything bad because there is an additional NULL check on the syscall entry, but if there happens to be a non-NULL value immediately after the system call table, this may result in local privilege escalation. Signed-off-by: Dan Rosenberg Cc: Cc: Chen Liqin Cc: Lennox Wu Cc: Eugene Teo Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/score/kernel/entry.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/score/kernel/entry.S b/arch/score/kernel/entry.S index 577abba3fac6..83bb96079c43 100644 --- a/arch/score/kernel/entry.S +++ b/arch/score/kernel/entry.S @@ -408,7 +408,7 @@ ENTRY(handle_sys) sw r9, [r0, PT_EPC] cmpi.c r27, __NR_syscalls # check syscall number - bgtu illegal_syscall + bgeu illegal_syscall slli r8, r27, 2 # get syscall routine la r11, sys_call_table -- 2.20.1