Merry Christmas! On 12/25/2013 6:36 AM, Nicolas Iooss wrote:
2013/12/23 Daniel J Walsh wrote:On 12/21/2013 09:27 AM, Nicolas Iooss wrote:My first message was not so clear. The check in libselinux/src/lsetfilecon.c line 35 [1] doesn't work because selinux_trans_to_raw_context(context, &rcontext) returns 0 and sets rcontext to NULL. This is why I'm asking to change the return value to something else if you want "cp -a" working. This fix is not to introduce a new feature but to fix an existing one. NicolasHow about if we add a check on lsetfilecon_raw? Changing the behaviour on selinux_trans_to_raw_context might cause other problems.I agree. I've found http://selinuxproject.org/page/LibselinuxAPISummary which says precisely for selinux_trans_to_raw_context: "If passed NULL, sets the returned context to NULL and returns 0." As this feature is documented, callers may rely on it and changing this behavior is likely to break things. Moreover setfilecon_raw and fsetfilecon_raw have the same NULL-pointer dereference issue. Do these functions need a patch too? By the way, other callers of selinux_trans_to_raw_context may also share this bug: avc_context_to_sid, security_canonicalize_context, security_check_context, etc. Is doing a segmentation fault the expected way to tell the caller it used a NULL pointer and should have manually checked every parameter before calling any libselinux function? Thanks and merry Christmas! Nicolasdiff --git a/libselinux/src/lsetfilecon.c b/libselinux/src/lsetfilecon.c index 461e3f7..af3775e 100644 - --- a/libselinux/src/lsetfilecon.c +++ b/libselinux/src/lsetfilecon.c @@ -9,6 +9,10 @@ int lsetfilecon_raw(const char *path, const security_context_t context) { + if (! context) { + errno=EINVAL; + return -1; + } return lsetxattr(path, XATTR_NAME_SELINUX, context, strlen(context) + 1 0); }_______________________________________________ Selinux mailing list Selinux@xxxxxxxxxxxxx To unsubscribe, send email to Selinux-leave@xxxxxxxxxxxxx. To get help, send an email containing "help" to Selinux-request@xxxxxxxxxxxxx.
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