From 081b387c7397498c583b1ba7c2fdaf4c6da6b538 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 10 Jun 2026 19:28:43 -0300 Subject: [PATCH] perf symbols: Fix bswap copy-paste error for 32-bit ELF p_filesz filename__read_build_id() byte-swaps 32-bit ELF program headers on cross-endian files, but line 178 passes p_offset to bswap_32() instead of p_filesz: hdrs.phdr32[i].p_filesz = bswap_32(hdrs.phdr32[i].p_offset); This clobbers p_filesz with the already-swapped p_offset value. The 64-bit path on line 182 is correct and swaps p_filesz from p_filesz. The consequence is that the PT_NOTE segment read uses the wrong size, which can cause either a short read (missing the build-id) or an oversized read (reading past the segment into adjacent data). Fix by swapping the correct field. Reported-by: sashiko-bot Fixes: fef8f648bb47726d ("perf symbol: Fix use-after-free in filename__read_build_id") Reviewed-by: Ian Rogers Cc: Ian Rogers Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol-minimal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c index 091071d06416..f4b0a711a62c 100644 --- a/tools/perf/util/symbol-minimal.c +++ b/tools/perf/util/symbol-minimal.c @@ -175,7 +175,7 @@ int filename__read_build_id(const char *filename, struct build_id *bid) if (elf32) { hdrs.phdr32[i].p_type = bswap_32(hdrs.phdr32[i].p_type); hdrs.phdr32[i].p_offset = bswap_32(hdrs.phdr32[i].p_offset); - hdrs.phdr32[i].p_filesz = bswap_32(hdrs.phdr32[i].p_offset); + hdrs.phdr32[i].p_filesz = bswap_32(hdrs.phdr32[i].p_filesz); } else { hdrs.phdr64[i].p_type = bswap_32(hdrs.phdr64[i].p_type); hdrs.phdr64[i].p_offset = bswap_64(hdrs.phdr64[i].p_offset);