Date: Fri, 26 Oct 2018 23:08:22 +0000 (UTC) From: Warner Losh <imp@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r339800 - head/stand/efi/loader Message-ID: <201810262308.w9QN8Mmk055424@repo.freebsd.org>
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Author: imp Date: Fri Oct 26 23:08:22 2018 New Revision: 339800 URL: https://svnweb.freebsd.org/changeset/base/339800 Log: Ensure we have a full EFI_DEVICE_PATH header before we try to look at its length. Some BIOSes pad the length of the device path to an even amount. When we had a device path that was somehow an odd length, we'd wind up having 1 byte left that we were bogusly interpreting as a full device path. We'd then dereference 2 bytes into that to get a length of the node, which had undefined (and quite undesired) effects. Sponsored by: Netflix, Inc MFC After: 3 days Modified: head/stand/efi/loader/main.c Modified: head/stand/efi/loader/main.c ============================================================================== --- head/stand/efi/loader/main.c Fri Oct 26 22:49:36 2018 (r339799) +++ head/stand/efi/loader/main.c Fri Oct 26 23:08:22 2018 (r339800) @@ -349,7 +349,7 @@ match_boot_info(EFI_LOADED_IMAGE *img __unused, char * edp = (EFI_DEVICE_PATH *)(walker + fplen); if ((char *)edp > ep) return NOT_SPECIFIC; - while (dp < edp) { + while (dp < edp && (size_t)(edp - dp) > sizeof(EFI_DEVICE_PATH)) { text = efi_devpath_name(dp); if (text != NULL) { printf(" BootInfo Path: %S\n", text);
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