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Revert "Problem with realpath interceptor" 

Breaks realpath(, nullptr) for all sanitizers.

Somehow INTERCEPT_FUNCTION and INTERCEPT_FUNCTION_VER return
false even if everything seemingly right.

And this is the issue for COMMON_INTERCEPT_FUNCTION_GLIBC_VER_MIN.
There is a check in every sanitlizer:
if (!INTERCEPT_FUNCTION_VER(name, ver) && !INTERCEPT_FUNCTION(name))

For non-versioned interceptors when INTERCEPT_FUNCTION returns false
it's not considered fatal, and it just prints a warning.

However INTERCEPT_FUNCTION_VER in this case will fallback to
INTERCEPT_FUNCTION replacing realpath with wrong version.

We need to investigate that before relanding the patch.

This reverts commit faef0d042f.
This commit is contained in:
Vitaly Buka 2021-08-25 13:34:19 -07:00
parent 3c11e5722c
commit 5213f307ab
1 changed files with 12 additions and 1 deletions
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13
compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
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@ -3664,11 +3664,22 @@ INTERCEPTOR(char *, realpath, const char *path, char *resolved_path) {
void *ctx;
COMMON_INTERCEPTOR_ENTER(ctx, realpath, path, resolved_path);
if (path) COMMON_INTERCEPTOR_READ_RANGE(ctx, path, internal_strlen(path) + 1);
// Workaround a bug in glibc where dlsym(RTLD_NEXT, ...) returns the oldest
// version of a versioned symbol. For realpath(), this gives us something
// (called __old_realpath) that does not handle NULL in the second argument.
// Handle it as part of the interceptor.
char *allocated_path = nullptr;
if (!resolved_path)
allocated_path = resolved_path = (char *)WRAP(malloc)(path_max + 1);
char *res = REAL(realpath)(path, resolved_path);
if (allocated_path && !res)
WRAP(free)(allocated_path);
if (res) COMMON_INTERCEPTOR_WRITE_RANGE(ctx, res, internal_strlen(res) + 1);
return res;
}
#define INIT_REALPATH COMMON_INTERCEPT_FUNCTION_GLIBC_VER_MIN(realpath, "GLIBC_2.3");
# define INIT_REALPATH COMMON_INTERCEPT_FUNCTION(realpath);
#else
#define INIT_REALPATH
#endif