Commit e7eb8726 authored Jun 23, 2008 by Cliff Wickman Committed by Ingo Molnar Jul 08, 2008

x86, SGI UV: uv_ptc_proc_write fix



Someone could write 0 bytes to /proc/sgi_uv/ptc_statistics,
causing
  optstr[count - 1] = '\0';
to write to who-knows-where.

(Andi Kleen noticed this need from a patch I sent for
 similar code in the ia64 world (sn2_ptc_proc_write()).)

(count less than zero is not possible here, as count is unsigned)

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent cef53278

arch/x86/kernel/tlb_uv.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -492,7 +492,7 @@ static ssize_t uv_ptc_proc_write(struct file file, const char __user user,
	long newmode;		long newmode;
	char optstr[64];		char optstr[64];

	if (count > 64)		if (count == 0 \|\| count > sizeof(optstr))
	return -EINVAL;		return -EINVAL;
	if (copy_from_user(optstr, user, count))		if (copy_from_user(optstr, user, count))
	return -EFAULT;		return -EFAULT;

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