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x86, SGI UV: uv_ptc_proc_write fix
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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>
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Cliff Wickman authored and Ingo Molnar committed Jul 8, 2008
1 parent cef5327 commit e7eb872
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion arch/x86/kernel/tlb_uv.c
Original file line number Diff line number Diff line change
Expand Up @@ -492,7 +492,7 @@ static ssize_t uv_ptc_proc_write(struct file *file, const char __user *user,
long newmode;
char optstr[64];

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