[Git][cmucl/cmucl][master] 2 commits: Fix #127: Linux unix:unix-getpwuid segfaults with invalid uid

[Raymond Toy (@rtoy)]

Raymond Toy pushed to branch master at cmucl / cmucl


Commits:
1af344b3 by Raymond Toy at 2022-08-08T17:39:43+00:00
Fix #127: Linux unix:unix-getpwuid segfaults with invalid uid

- - - - -
9bba5bc4 by Raymond Toy at 2022-08-08T17:39:45+00:00
Merge branch 'issue-127-getpwuid-segfault' into 'master'

Fix #127: Linux unix:unix-getpwuid segfaults with invalid uid

Closes #127

See merge request cmucl/cmucl!86
- - - - -


2 changed files:

- src/code/unix.lisp
- tests/issues.lisp


Changes:

=====================================
src/code/unix.lisp
=====================================
@@ -2748,9 +2748,12 @@
 
 #+linux
 (defun unix-getpwuid (uid)
-  _N"Return a USER-INFO structure for the user identified by UID, or NIL if not found."
+  "Return a USER-INFO structure for the user identified by UID.  If
+  not found, NIL is returned with a second value indicating the cause
+  of the failure.  In particular, if the second value is 0 (or
+  ENONENT, ESRCH, EBADF, etc.), then the uid was not found."
   (declare (type unix-uid uid))
-  (with-alien ((buf (array c-call:char 1024))
+  (with-alien ((buf (array c-call:char 16384))
 	       (user-info (struct passwd))
                (result (* (struct passwd))))
     (let ((returned
@@ -2767,15 +2770,16 @@
 	    (cast buf (* c-call:char))
 	    1024
             (addr result))))
-      (when (zerop returned)
-        (make-user-info
-         :name (string (cast (slot result 'pw-name) c-call:c-string))
-         :password (string (cast (slot result 'pw-passwd) c-call:c-string))
-         :uid (slot result 'pw-uid)
-         :gid (slot result 'pw-gid)
-         :gecos (string (cast (slot result 'pw-gecos) c-call:c-string))
-         :dir (string (cast (slot result 'pw-dir) c-call:c-string))
-         :shell (string (cast (slot result 'pw-shell) c-call:c-string)))))))
+      (if (not (zerop (sap-int (alien-sap result))))
+          (make-user-info
+           :name (string (cast (slot result 'pw-name) c-call:c-string))
+           :password (string (cast (slot result 'pw-passwd) c-call:c-string))
+           :uid (slot result 'pw-uid)
+           :gid (slot result 'pw-gid)
+           :gecos (string (cast (slot result 'pw-gecos) c-call:c-string))
+           :dir (string (cast (slot result 'pw-dir) c-call:c-string))
+           :shell (string (cast (slot result 'pw-shell) c-call:c-string)))
+	  (values nil returned)))))
 
 ;;; Getrusage is not provided in the C library on Solaris 2.4, and is
 ;;; rather slow on later versions so the "times" system call is


=====================================
tests/issues.lisp
=====================================
@@ -570,3 +570,12 @@
              (terpri s)
              (fresh-line s))
            a)))
+
+(define-test issue.127
+    (:tag :issues)
+  ;; Let's just start at uid 10000 and keep going up until we fail.
+  ;; There should be no segfaults when we find an invalid uid.
+  (loop for uid from 10000
+	with user-info = (unix:unix-getpwuid uid)
+	while user-info
+	finally (assert-false user-info)))



View it on GitLab: https://gitlab.common-lisp.net/cmucl/cmucl/-/compare/00907500388dcbabd1130618f67028656fa1f396...9bba5bc4fbb1f4b901b0f53db07e28a418ded7cc

-- 
View it on GitLab: https://gitlab.common-lisp.net/cmucl/cmucl/-/compare/00907500388dcbabd1130618f67028656fa1f396...9bba5bc4fbb1f4b901b0f53db07e28a418ded7cc
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