From: Andrew Tridgell <andrew@tridgell.net>
Date: Sat, 13 Jun 2026 20:44:21 +0000 (+1000)
Subject: generator: don't read an unstat'd sx.st when creating a device/special
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7bebcee20fc5967c375edd25b825af0c43d96ed5;p=thirdparty%2Frsync.git

generator: don't read an unstat'd sx.st when creating a device/special

this fixes a valgrind error where we could read an uninitialised sx.st
field when we don't fill the stat data.

Also drop the now-obsolete testsuite/valgrind.supp stanzas for these
reads (atomic_create/delete_item, plus the rwrite strlcpy over-read that
master already fixed) -- they are no longer needed now the reads are gone.

Thanks to report from Michael Mess <michael@michaelmess.de>
---

diff --git a/generator.c b/generator.c
index 09e276d1..107c925a 100644
--- a/generator.c
+++ b/generator.c
@@ -1230,7 +1230,7 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
 	static int need_fuzzy_dirlist = 0;
 	struct file_struct *fuzzy_file = NULL;
 	int fd = -1, f_copy = -1;
-	stat_x sx, real_sx;
+	stat_x sx = {0}, real_sx;
 	STRUCT_STAT partial_st;
 	struct file_struct *back_file = NULL;
 	int statret, real_ret, stat_errno;
@@ -1628,6 +1628,10 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
 	 || (preserve_specials && ftype == FT_SPECIAL)) {
 		dev_t rdev;
 		int del_for_flag;
+		/* Whether the dest existed, captured before the type-mismatch
+		 * flip below clears statret -- so atomic_create() gets a delete
+		 * flag (and reads sx.st) only when sx.st was actually stat'd. */
+		int dest_existed = (statret == 0);
 		if (ftype == FT_DEVICE) {
 			uint32 *devp = F_RDEV_P(file);
 			rdev = MAKEDEV(DEV_MAJOR(devp), DEV_MINOR(devp));
@@ -1674,7 +1678,7 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
 				fname, (int)file->mode,
 				(long)major(rdev), (long)minor(rdev));
 		}
-		if (atomic_create(file, fname, NULL, NULL, rdev, &sx, del_for_flag)) {
+		if (atomic_create(file, fname, NULL, NULL, rdev, &sx, dest_existed ? del_for_flag : 0)) {
 			set_file_attrs(fname, file, NULL, NULL, 0);
 			if (itemizing) {
 				itemize(fnamecmp, file, ndx, statret, &sx,
diff --git a/testsuite/valgrind.supp b/testsuite/valgrind.supp
index b0cf91ea..ddaefd08 100644
--- a/testsuite/valgrind.supp
+++ b/testsuite/valgrind.supp
@@ -25,35 +25,6 @@
    fun:main
 }
 
-# rwrite() strlcpy()s a peer log message.  read_a_msg() hands it exactly
-# msg_bytes valid bytes with no terminating NUL; the copy is bounded to len,
-# but strlcpy over-reads past the message to compute its (discarded) return
-# length.  Harmless read of one+ uninitialised stack byte.
-{
-   rsync-rwrite-strlcpy-peer-msg
-   Memcheck:Cond
-   fun:strlcpy
-   fun:strlcpy
-   fun:rwrite
-}
-
-# atomic_create()/delete_item() test sxp->st.st_mode when replacing an
-# existing item.  Under fakeroot the faked stat overlay leaves mode bits that
-# valgrind treats as uninitialised.  Pre-existing hard-link code; fakeroot
-# artifact, not an rsync read of uninitialised memory.
-{
-   rsync-atomic-create-stmode
-   Memcheck:Cond
-   fun:atomic_create
-   fun:recv_generator
-}
-{
-   rsync-delete-item-stmode
-   Memcheck:Cond
-   fun:delete_item
-   fun:atomic_create
-}
-
 # libxxhash returns an internally-aligned XXH3 state whose pointer is offset
 # from the malloc base, so valgrind sees only an interior pointer and reports
 # the one-time checksum state as "possibly lost".  Alignment artifact.