Commit e7eb8726 authored by Cliff Wickman's avatar Cliff Wickman Committed by Ingo Molnar

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: default avatarCliff Wickman <cpw@sgi.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent cef53278
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...@@ -492,7 +492,7 @@ static ssize_t uv_ptc_proc_write(struct file *file, const char __user *user, ...@@ -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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