@matheusbsbs / matheus-bagliano / commits / 2f8952250a

regex: add regexec_buf() that can work on a non NUL-terminated string

We just introduced a test that demonstrates that our sloppy use of regexec() on a mmap()ed area can result in incorrect results or even hard crashes. So what we need to fix this is a function that calls regexec() on a length-delimited, rather than a NUL-terminated, string. Happily, there is an extension to regexec() introduced by the NetBSD project and present in all major regex implementation including Linux', MacOSX' and the one Git includes in compat/regex/: by using the (non-POSIX) REG_STARTEND flag, it is possible to tell the regexec() function that it should only look at the offsets between pmatch[0].rm_so and pmatch[0].rm_eo. That is exactly what we need. Since support for REG_STARTEND is so widespread by now, let's just introduce a helper function that always uses it, and tell people on a platform whose regex library does not support it to use the one from our compat/regex/ directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Johannes Schindelin committed Sep 21, 2016 at 20:24 UTC 2f8952250a84313b74f96abb7b035874854cf202

2 files changed +15 -1

Makefile

+2 -1

@@ -296,7 +296,8 @@ all::

296 # Define USE_NED_ALLOCATOR if you want to replace the platforms default

297 # memory allocators with the nedmalloc allocator written by Niall Douglas.

298 #

299 -# Define NO_REGEX if you have no or inferior regex support in your C library.

299 +# Define NO_REGEX if your C library lacks regex support with REG_STARTEND

300 +# feature.

301 #

302 # Define HAVE_DEV_TTY if your system can open /dev/tty to interact with the

303 # user.

git-compat-util.h

+13

@@ -942,6 +942,19 @@ void git_qsort(void *base, size_t nmemb, size_t size,

942 #define qsort git_qsort

943 #endif

944

945 +#ifndef REG_STARTEND

946 +#error "Git requires REG_STARTEND support. Compile with NO_REGEX=NeedsStartEnd"

947 +#endif

948 +

949 +static inline int regexec_buf(const regex_t *preg, const char *buf, size_t size,

950 + size_t nmatch, regmatch_t pmatch[], int eflags)

951 +{

952 + assert(nmatch > 0 && pmatch);

953 + pmatch[0].rm_so = 0;

954 + pmatch[0].rm_eo = size;

955 + return regexec(preg, buf, nmatch, pmatch, eflags | REG_STARTEND);

956 +}

957 +

958 #ifndef DIR_HAS_BSD_GROUP_SEMANTICS

959 # define FORCE_DIR_SET_GID S_ISGID

960 #else