On Thu, 12 Mar 2026 21:03:52 +0000 Josh Law <[email protected]> wrote:
> 12 Mar 2026 21:02:51 Steven Rostedt <[email protected]>: > > > On Thu, 12 Mar 2026 19:11:41 +0000 > > Josh Law <[email protected]> wrote: > > > >> From: Josh Law <[email protected]> > >> > >> __xbc_open_brace() pushes entries with post-increment > >> (open_brace[brace_index++]), so brace_index always points one past > >> the last valid entry. xbc_verify_tree() reads open_brace[brace_index] > >> to report which brace is unclosed, but this is one past the last > >> pushed entry and contains stale/zero data, causing the error message > >> to reference the wrong node. > >> > >> Use open_brace[brace_index - 1] to correctly identify the unclosed > >> brace. brace_index is known to be > 0 here since we are inside the > >> if (brace_index) guard. > >> > >> Signed-off-by: Josh Law <[email protected]> > > > > Nice catch. May I ask how you found this. > > > > Reviewed-by: Steven Rostedt (Google) <[email protected]> Thanks for patch and review! > > > > -- Steve > > > >> --- > >> lib/bootconfig.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/lib/bootconfig.c b/lib/bootconfig.c > >> index 2bcd5c2aa87e..a1e6a2e14b01 100644 > >> --- a/lib/bootconfig.c > >> +++ b/lib/bootconfig.c > >> @@ -802,7 +802,7 @@ static int __init xbc_verify_tree(void) > >> > >> /* Brace closing */ > >> if (brace_index) { > >> - n = &xbc_nodes[open_brace[brace_index]]; > >> + n = &xbc_nodes[open_brace[brace_index - 1]]; > >> return xbc_parse_error("Brace is not closed", > >> xbc_node_get_data(n)); > >> } > > Hi Steve, > Thanks for the review! > I found this while doing a manual audit of the bootconfig parser's error > handling. I noticed that the post-increment in __xbc_open_brace() didn't seem > to align with how xbc_verify_tree() was accessing the index. I verified it by > intentionally passing a malformed config with an unclosed brace and saw it reporting a 'stale' or incorrect node location Thanks, I confirmed it with below config. $ cat samples/bad-non-closed-brace.bconf foo { bar { buz } This closed the 2nd `{`, but not close the first one. Without patch; $ ./bootconfig samples/bad-non-closed-brace.bconf Parse Error: Brace is not closed at 2:2 With this fix; $ ./bootconfig samples/bad-non-closed-brace.bconf Parse Error: Brace is not closed at 1:1 Than you! -- Masami Hiramatsu (Google) <[email protected]>
