[PATCH] [4/50] xtensa: prevent arbitrary read in ptrace

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>

[ upstream commit 0d0138ebe24b94065580bd2601f8bb7eb6152f56 ]

Prevent an arbitrary kernel read.  Check the user pointer with access_ok()
before copying data in.

[akpm@xxxxxxxxxxxxxxxxxxxx: s/EIO/EFAULT/]
Signed-off-by: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>
Cc: Christian Zankel <chris@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Index: linux-2.6.35.y/arch/xtensa/kernel/ptrace.c
===================================================================
--- linux-2.6.35.y.orig/arch/xtensa/kernel/ptrace.c
+++ linux-2.6.35.y/arch/xtensa/kernel/ptrace.c
@@ -147,6 +147,9 @@ int ptrace_setxregs(struct task_struct *
 	elf_xtregs_t *xtregs = uregs;
 	int ret = 0;
 
+	if (!access_ok(VERIFY_READ, uregs, sizeof(elf_xtregs_t)))
+		return -EFAULT;
+
 #if XTENSA_HAVE_COPROCESSORS
 	/* Flush all coprocessors before we overwrite them. */
 	coprocessor_flush_all(ti);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/