+ lib-bootconfig-fix-snprintf-truncation-check-in-xbc_node_compose_key_after.patch added to mm-nonmm-unstable branch

+ lib-bootconfig-fix-snprintf-truncation-check-in-xbc_node_compose_key_after.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: lib/bootconfig: fix snprintf truncation check in xbc_node_compose_key_after()
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     lib-bootconfig-fix-snprintf-truncation-check-in-xbc_node_compose_key_after.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-bootconfig-fix-snprintf-truncation-check-in-xbc_node_compose_key_after.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Josh Law <objecting@objecting.org>
Subject: lib/bootconfig: fix snprintf truncation check in xbc_node_compose_key_after()
Date: Thu, 12 Mar 2026 19:11:43 +0000

snprintf() returns the number of characters that would have been written
excluding the NUL terminator.  Output is truncated when the return value
is >= the buffer size, not just > the buffer size.

When ret == size, the current code takes the non-truncated path, advancing
buf by ret and reducing size to 0.  This is wrong because the output was
actually truncated (the last character was replaced by NUL).  Fix by using
>= so the truncation path is taken correctly.

Link: https://lkml.kernel.org/r/20260312191143.28719-4-objecting@objecting.org
Signed-off-by: Josh Law <objecting@objecting.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/bootconfig.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/lib/bootconfig.c~lib-bootconfig-fix-snprintf-truncation-check-in-xbc_node_compose_key_after
+++ a/lib/bootconfig.c
@@ -316,7 +316,7 @@ int __init xbc_node_compose_key_after(st
 			       depth ? "." : "");
 		if (ret < 0)
 			return ret;
-		if (ret > size) {
+		if (ret >= size) {
 			size = 0;
 		} else {
 			size -= ret;
_

Patches currently in -mm which might be from objecting@objecting.org are

lib-maple_tree-fix-swapped-arguments-in-mas_safe_pivot-call.patch
lib-glob-fix-grammar-and-replace-non-inclusive-terminology.patch
lib-glob-add-explicit-include-for-exporth.patch
lib-glob-replace-bitwise-or-with-logical-operation-on-boolean.patch
lib-glob-clean-up-bool-abuse-in-pointer-arithmetic.patch
lib-uuid-fix-typo-reversion-to-revision-in-comment.patch
lib-inflate-fix-memory-leak-in-inflate_fixed-on-inflate_codes-failure.patch
lib-inflate-fix-memory-leak-in-inflate_dynamic-on-inflate_codes-failure.patch
lib-inflate-fix-grammar-in-comment-variable-to-variables.patch
lib-inflate-fix-typo-this-results-to-the-results-in-comment.patch
lib-bug-fix-inconsistent-capitalization-in-bug-message.patch
lib-bug-remove-unnecessary-variable-initializations.patch
lib-idr-fix-ida_find_first_range-missing-ids-across-chunk-boundaries.patch
lib-decompress_bunzip2-fix-32-bit-shift-undefined-behavior.patch
maintainers-add-josh-law-as-reviewer-for-library-code.patch
lib-bootconfig-fix-typo-budy-in-_xbc_exit-comment.patch
lib-ts_bm-fix-integer-overflow-in-pattern-length-calculation.patch
lib-ts_kmp-fix-integer-overflow-in-pattern-length-calculation.patch
lib-bootconfig-fix-off-by-one-in-xbc_verify_tree-unclosed-brace-error.patch
lib-bootconfig-check-bounds-before-writing-in-__xbc_open_brace.patch
lib-bootconfig-fix-snprintf-truncation-check-in-xbc_node_compose_key_after.patch