From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BDFF61CAA6D; Tue, 21 Jul 2026 18:10:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657453; cv=none; b=BW9U1xqn9ewdkHohOpPlJU4v8v71dYVHC/wK+itdrY4/H2UypMG7QiUzXfA52dUHc2jcf/UD1W1wwWp2AZzfcdZ62As4cZIQ6LXGYWC7gmqBMIlXT6ayVZu36Ln4GaX4aMo5l5C0wHT4284l8kyu0+N2gQlYDanBGEZKQjFCRp0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657453; c=relaxed/simple; bh=2LO14Ql+BbRvyKg8Qr7A/C88rykveSsBD49clH8bdQ8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=m49vbPeVTXgHHxOEI0YwnuD2l1/p2hPJ94i3NKF4ptdufFhdksoQuVtWY0gjm2ssA8yMcsIObtBXska9ZkuMoCqjVZiml8TSR3SESlTk0qaxPe/ZVyizKD+W2h9yraPllKL6fTWHI16IM9J/CepTYTtayBsMyW+/6wGgnuNJ75Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wuA3GvgJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="wuA3GvgJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D88281F000E9; Tue, 21 Jul 2026 18:10:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784657452; bh=LlWvjTAvx/vD5iVy6dHlPHTAPtBabEoCO1NuqMwKfgI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=wuA3GvgJ154Flbz1qpFt2kmJIj0xfu6E2712TeypKX4RLTaAJaB+/E3U/mXiFLnME 3I3cGl+O0U8iodQRY31eScrVuaj5b2x+vs8S2pzL1OEQg5eWm3XuE/B4rlt6cqr63/ chFf+7S9zodlilDoAN++mSIWRBnj3bV/DvxeBAcs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, sashiko-bot , Ian Rogers , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH 6.18 0770/1611] perf symbols: Validate p_filesz before use in filename__read_build_id() Date: Tue, 21 Jul 2026 17:14:46 +0200 Message-ID: <20260721152532.705159815@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnaldo Carvalho de Melo [ Upstream commit 2a3716544359d4312c81b0fa909a13301186da17 ] filename__read_build_id() stores ELF p_filesz in a ssize_t variable. A crafted 32-bit ELF with p_filesz = 0xFFFFFFFF produces ssize_t value -1. The comparison `p_filesz > buf_size` evaluates false because signed -1 is less than any non-negative buf_size, so the realloc is skipped and buf remains NULL. The subsequent read(fd, NULL, -1) returns -1, which equals p_filesz, passing the error check. read_build_id() then dereferences the NULL buffer. Add an explicit check for p_filesz <= 0 before using the value, catching both zero-length and sign-wrapped negative sizes from crafted ELF files. Reported-by: sashiko-bot Fixes: ba0b7081f7a521d7 ("perf symbol-minimal: Fix ehdr reading 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 Signed-off-by: Sasha Levin --- tools/perf/util/symbol-minimal.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c index 39b806651b9258..aa931a0015c10b 100644 --- a/tools/perf/util/symbol-minimal.c +++ b/tools/perf/util/symbol-minimal.c @@ -179,6 +179,9 @@ int filename__read_build_id(const char *filename, struct build_id *bid, bool blo continue; p_filesz = elf32 ? hdrs.phdr32[i].p_filesz : hdrs.phdr64[i].p_filesz; + /* ssize_t can go negative with crafted ELF p_filesz values */ + if (p_filesz <= 0) + continue; if (p_filesz > buf_size) { void *tmp; -- 2.53.0