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| author | Ryan Mallon <rmallon@gmail.com> | 2014-04-03 14:48:37 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-03 16:21:07 -0700 |
| commit | 708d96fd060bd1e729fc93048cea8901f8bacb7c (patch) | |
| tree | 1dc1656df18d946b6521f1c1c6b676dd8b2b465b /lib | |
| parent | 28ab49ff7f3dcaf4df8d2bd0d4099b8c08285ed7 (diff) | |
| download | linux-stable-708d96fd060bd1e729fc93048cea8901f8bacb7c.tar.gz linux-stable-708d96fd060bd1e729fc93048cea8901f8bacb7c.tar.bz2 linux-stable-708d96fd060bd1e729fc93048cea8901f8bacb7c.zip | |
vsprintf: remove %n handling
All in-kernel users of %n in format strings have now been removed and
the %n directive is ignored. Remove the handling of %n so that it is
treated the same as any other invalid format string directive. Keep a
warning in place to deter new instances of %n in format strings.
Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/vsprintf.c | 45 |
1 files changed, 9 insertions, 36 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 5e2cf6f342f8..0648291cdafe 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -364,7 +364,6 @@ enum format_type { FORMAT_TYPE_SHORT, FORMAT_TYPE_UINT, FORMAT_TYPE_INT, - FORMAT_TYPE_NRCHARS, FORMAT_TYPE_SIZE_T, FORMAT_TYPE_PTRDIFF }; @@ -1538,10 +1537,6 @@ qualifier: return fmt - start; /* skip alnum */ - case 'n': - spec->type = FORMAT_TYPE_NRCHARS; - return ++fmt - start; - case '%': spec->type = FORMAT_TYPE_PERCENT_CHAR; return ++fmt - start; @@ -1564,6 +1559,15 @@ qualifier: case 'u': break; + case 'n': + /* + * Since %n poses a greater security risk than utility, treat + * it as an invalid format specifier. Warn about its use so + * that new instances don't get added. + */ + WARN_ONCE(1, "Please remove ignored %%n in '%s'\n", fmt); + /* Fall-through */ + default: spec->type = FORMAT_TYPE_INVALID; return fmt - start; @@ -1737,20 +1741,6 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args) ++str; break; - case FORMAT_TYPE_NRCHARS: { - /* - * Since %n poses a greater security risk than - * utility, ignore %n and skip its argument. - */ - void *skip_arg; - - WARN_ONCE(1, "Please remove ignored %%n in '%s'\n", - old_fmt); - - skip_arg = va_arg(args, void *); - break; - } - default: switch (spec.type) { case FORMAT_TYPE_LONG_LONG: @@ -2025,19 +2015,6 @@ do { \ fmt++; break; - case FORMAT_TYPE_NRCHARS: { - /* skip %n 's argument */ - u8 qualifier = spec.qualifier; - void *skip_arg; - if (qualifier == 'l') - skip_arg = va_arg(args, long *); - else if (_tolower(qualifier) == 'z') - skip_arg = va_arg(args, size_t *); - else - skip_arg = va_arg(args, int *); - break; - } - default: switch (spec.type) { @@ -2196,10 +2173,6 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf) ++str; break; - case FORMAT_TYPE_NRCHARS: - /* skip */ - break; - default: { unsigned long long num; |