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Be strict, but not that strict.

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Certain apps decide that they want to chmod() their private data
directories to gain more security.  We still want to carefully
enforce owner UID/GID, but relax the mode check for now.

Bug: 26549892
Change-Id: I362d530ba0b20fb23f427ac082ee003864adc57d
This commit is contained in:
Jeff Sharkey 2016-01-14 11:53:42 -07:00
parent 27f961f93d
commit 814640315a
2 changed files with 13 additions and 4 deletions
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2
include/cutils/fs.h
View file

@ -47,7 +47,7 @@ extern int fs_prepare_dir(const char* path, mode_t mode, uid_t uid, gid_t gid);
/*
* Ensure that directory exists with given mode and owners. If it exists
* with a different mode or owners, they are not fixed and -1 is returned.
* with different owners, they are not fixed and -1 is returned.
*/
extern int fs_prepare_dir_strict(const char* path, mode_t mode, uid_t uid, gid_t gid);

15
libcutils/fs.c
View file

@ -55,13 +55,22 @@ static int fs_prepare_dir_impl(const char* path, mode_t mode, uid_t uid, gid_t g
ALOGE("Not a directory: %s", path);
return -1;
}
if (((sb.st_mode & ALL_PERMS) == mode) && (sb.st_uid == uid) && (sb.st_gid == gid)) {
int owner_match = ((sb.st_uid == uid) && (sb.st_gid == gid));
int mode_match = ((sb.st_mode & ALL_PERMS) == mode);
if (owner_match && mode_match) {
return 0;
} else if (allow_fixup) {
goto fixup;
} else {
ALOGE("Path %s exists with unexpected permissions", path);
return -1;
if (!owner_match) {
ALOGE("Expected path %s with owner %d:%d but found %d:%d",
path, uid, gid, sb.st_uid, sb.st_gid);
return -1;
} else {
ALOGW("Expected path %s with mode %o but found %o",
path, mode, (sb.st_mode & ALL_PERMS));
return 0;
}
}
create: