Commit c6b40d16 authored May 08, 2007 by Johannes Berg Committed by Linus Torvalds May 08, 2007

fix sscanf %n match at end of input string



I was playing with some code that sometimes got a string where a %n
match should have been done where the input string ended, for example
like this:

  sscanf("abc123", "abc%d%n", &a, &n);  /* doesn't work */
  sscanf("abc123a", "abc%d%n", &a, &n); /* works */

However, the scanf function in the kernel doesn't convert the %n in that
case because it has already matched the complete input after %d and just
completely stops matching then. This patch fixes that.

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 757dea93

lib/vsprintf.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -825,6 +825,17 @@ int vsscanf(const char * buf, const char * fmt, va_list args)
		break;
		str = next;
		}

		/*
		* Now we've come all the way through so either the input string or the
		* format ended. In the former case, there can be a %n at the current
		* position in the format that needs to be filled.
		*/
		if (fmt == '%' && (fmt + 1) == 'n') {
		int p = (int )va_arg(args, int *);
		*p = str - buf;
		}

		return num;
		}

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