On Wed, Aug 8, 2012 at 10:34 AM, Anna Zaks <[email protected]> wrote: > > On Aug 7, 2012, at 12:01 PM, Matt Beaumont-Gay wrote: > >> Should we have similar treatment for strncpy? >> >> Also, a nit: >> void f(char* s, char* d) { >> strncat(d, s, sizeof(d)); >> } >> >> test.cc:5:17: warning: the value of the size argument in 'strncat' is >> too large, might lead to a buffer overflow [-Wstrncat-size] >> strncat(d, s, sizeof(d)); >> ^~~~~~~~~ >> >> Here, sizeof(d) is not necessarily too large, just wrong. > > It is too large in this case - it should be at least 1 less than sizeof(d), > even if d is empty.
My point is that d is a pointer here, not an array. > > Anna. >> >> On Tue, Aug 7, 2012 at 11:36 AM, Anna Zaks <[email protected]> wrote: >>> Author: zaks >>> Date: Tue Aug 7 13:36:58 2012 >>> New Revision: 161440 >>> >>> URL: http://llvm.org/viewvc/llvm-project?rev=161440&view=rev >>> Log: >>> Turn on strncat-size warning implemented a while ago. >>> >>> Warns on anti-patterns/typos in the 'size' argument to strncat. The >>> correct size argument should look like the following: >>> - strncat(dst, src, sizeof(dst) - strlen(dest) - 1); >>> >>> We warn on: >>> - sizeof(dst) >>> - sizeof(src) >>> - sizeof(dst) - strlen(dst) >>> - sizeof(src) - anything >>> >>> (This has been implemented in void Sema::CheckStrncatArguments().) >>> >>> Modified: >>> cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td >>> cfe/trunk/test/Analysis/cstring-syntax.c >>> >>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td >>> URL: >>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=161440&r1=161439&r2=161440&view=diff >>> ============================================================================== >>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original) >>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Aug 7 >>> 13:36:58 2012 >>> @@ -373,9 +373,9 @@ >>> >>> def warn_strncat_large_size : Warning< >>> "the value of the size argument in 'strncat' is too large, might lead to >>> a " >>> - "buffer overflow">, InGroup<StrncatSize>, DefaultIgnore; >>> + "buffer overflow">, InGroup<StrncatSize>, DefaultWarnNoWerror; >>> def warn_strncat_src_size : Warning<"size argument in 'strncat' call >>> appears " >>> - "to be size of the source">, InGroup<StrncatSize>, DefaultIgnore; >>> + "to be size of the source">, InGroup<StrncatSize>, DefaultWarnNoWerror; >>> def note_strncat_wrong_size : Note< >>> "change the argument to be the free space in the destination buffer minus >>> " >>> "the terminating null byte">; >>> >>> Modified: cfe/trunk/test/Analysis/cstring-syntax.c >>> URL: >>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/cstring-syntax.c?rev=161440&r1=161439&r2=161440&view=diff >>> ============================================================================== >>> --- cfe/trunk/test/Analysis/cstring-syntax.c (original) >>> +++ cfe/trunk/test/Analysis/cstring-syntax.c Tue Aug 7 13:36:58 2012 >>> @@ -1,4 +1,4 @@ >>> -// RUN: %clang_cc1 -analyze -analyzer-checker=unix.cstring.BadSizeArg >>> -analyzer-store=region -Wno-strlcpy-strlcat-size -Wno-sizeof-array-argument >>> -Wno-sizeof-pointer-memaccess -verify %s >>> +// RUN: %clang_cc1 -analyze -analyzer-checker=unix.cstring.BadSizeArg >>> -analyzer-store=region -Wno-strncat-size -Wno-strlcpy-strlcat-size >>> -Wno-sizeof-array-argument -Wno-sizeof-pointer-memaccess -verify %s >>> >>> typedef __SIZE_TYPE__ size_t; >>> char *strncat(char *, const char *, size_t); >>> >>> >>> _______________________________________________ >>> cfe-commits mailing list >>> [email protected] >>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits > _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
