How is my string potentially unsecure?

Question

Possible Duplicate:
Calling NSLog from C++: “Format string is not a string literal (potentially insecure)”
Why is my string potentially unsecure in my iOS application?

I have this code to log the number of elements in my NSMutableDictionary called "myDictionary" in objective-c.

NSLog([NSString stringWithFormat:@"%d", [myDictionary count]]);

XCode warns me that "Format string is not a string literal. Potentially insecure."

Why? Aren't I using a secure formatted string as opposed to directly casting the count?

Duplicates: [one](http://stackoverflow.com/questions/9793199/calling-nslog-from-c-format-string-is-not-a-string-literal-potentially-inse), [two](http://stackoverflow.com/questions/9961363/why-is-my-string-potentially-unsecure-in-my-ios-application). — Kurt Revis, Apr 03 '12 at 00:44

score 6 · Answer 1 · answered Apr 03 '12 at 00:28

6

NSLog() already assumes that you'll be passing in a formatted string. Try this instead:

NSLog(@"%d", [myDictionary count]);

answered Apr 03 '12 at 00:28

Reed Olsen

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score 4 · Accepted Answer · answered Apr 03 '12 at 00:31

The string you pass to NSLog is interpreted like a format string, so the appropriate way to do this is NSLog(@"%d", myDictionary.count);.

The reason it's "unsafe" is that it's possible to crash the program in cases like this:

NSString *someString = @"The integer format specifier is %d";
NSLog([NSString stringWithFormat:@"%@", someString]);

The input to NSLog is treated like a format string, but there's no corresponding value for the %d at the end. In your case it's not a problem, but the compiler isn't smart enough to figure that out.

How is my string potentially unsecure?

2 Answers2