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Blackfin: add missing access_ok() checks to user functions
The core string/clear user functions weren't checking the user pointers which caused kernel crashes with some bad programs and tests (like LTP). Signed-off-by: Robin Getz <robin.getz@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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parent
685a694f06
commit
a8372b5ca6
1 changed files with 20 additions and 5 deletions
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@ -233,16 +233,29 @@ strncpy_from_user(char *dst, const char *src, long count)
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}
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/*
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* Return the size of a string (including the ending 0)
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* Get the size of a string in user space.
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* src: The string to measure
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* n: The maximum valid length
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*
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* Return 0 on exception, a value greater than N if too long
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* Get the size of a NUL-terminated string in user space.
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*
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* Returns the size of the string INCLUDING the terminating NUL.
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* On exception, returns 0.
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* If the string is too long, returns a value greater than n.
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*/
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static inline long strnlen_user(const char *src, long n)
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static inline long __must_check strnlen_user(const char *src, long n)
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{
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return (strlen(src) + 1);
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if (!access_ok(VERIFY_READ, src, 1))
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return 0;
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return strnlen(src, n) + 1;
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}
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#define strlen_user(str) strnlen_user(str, 32767)
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static inline long __must_check strlen_user(const char *src)
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{
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if (!access_ok(VERIFY_READ, src, 1))
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return 0;
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return strlen(src) + 1;
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}
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/*
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* Zero Userspace
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@ -251,6 +264,8 @@ static inline long strnlen_user(const char *src, long n)
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static inline unsigned long __must_check
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__clear_user(void *to, unsigned long n)
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{
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if (!access_ok(VERIFY_WRITE, to, n))
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return n;
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memset(to, 0, n);
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return 0;
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}
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