lib/bootconfig: fix snprintf truncation check in xbc_node_compose_key_after()

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commit 1120a36bb1 upstream.

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://lore.kernel.org/all/20260312191143.28719-4-objecting@objecting.org/

Fixes: 76db5a27a8 ("bootconfig: Add Extra Boot Config support")
Cc: stable@vger.kernel.org
Signed-off-by: Josh Law <objecting@objecting.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Josh Law 2026-03-12 19:11:43 +00:00 • committed by Greg Kroah-Hartman

parent 3dd0812a7c

commit 6ab599749f

1 changed files with 1 additions and 1 deletions

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lib/bootconfig.c

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