projects / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| d04fb4ee MT |
1 | From b98ba8921010d03f46704a476c69861515deb1ca Mon Sep 17 00:00:00 2001 |
| 2 | From: Peter Jones <pjones@redhat.com> | |
| 3 | Date: Mon, 7 Jan 2019 10:30:59 -0500 | |
| 4 | Subject: [PATCH] dp.h: make format_guid() handle misaligned guid pointers | |
| 5 | safely. | |
| 6 | ||
| 7 | GCC 9 adds -Werror=address-of-packed-member, which causes us to see the | |
| 8 | build error reported at | |
| 9 | https://bugzilla.opensuse.org/show_bug.cgi?id=1120862 . | |
| 10 | ||
| 11 | That bug report shows us the following: | |
| 12 | ||
| 13 | In file included from dp.c:26: | |
| 14 | dp.h: In function 'format_vendor_helper': | |
| 15 | dp.h:120:37: error: taking address of packed member of 'struct <anonymous>' may result in an unaligned pointer value [-Werror=address-of-packed-member] | |
| 16 | 120 | format_guid(buf, size, off, label, &dp->hw_vendor.vendor_guid); | |
| 17 | | ^~~~~~~~~~~~~~~~~~~~~~~~~~ | |
| 18 | dp.h:74:25: note: in definition of macro 'format_guid' | |
| 19 | 74 | _rc = efi_guid_to_str(guid, &_guidstr); \ | |
| 20 | | ^~~~ | |
| 21 | cc1: all warnings being treated as errors | |
| 22 | ||
| 23 | This patch makes format_guid() use a local variable as a bounce buffer | |
| 24 | in the case that the guid we're passed is aligned as chaotic neutral. | |
| 25 | ||
| 26 | Note that this only fixes this instance and there may be others that bz | |
| 27 | didn't show because it exited too soon, and I don't have a gcc 9 build | |
| 28 | in front of me right now. | |
| 29 | ||
| 30 | Signed-off-by: Peter Jones <pjones@redhat.com> | |
| 31 | --- | |
| 32 | src/dp.h | 11 +++++++++-- | |
| 33 | 1 file changed, 9 insertions(+), 2 deletions(-) | |
| 34 | ||
| 35 | diff --git a/src/dp.h b/src/dp.h | |
| 36 | index aa4e390..20cb608 100644 | |
| 37 | --- a/src/dp.h | |
| 38 | +++ b/src/dp.h | |
| 39 | @@ -70,8 +70,15 @@ | |
| 40 | #define format_guid(buf, size, off, dp_type, guid) ({ \ | |
| 41 | int _rc; \ | |
| 42 | char *_guidstr = NULL; \ | |
| 43 | - \ | |
| 44 | - _rc = efi_guid_to_str(guid, &_guidstr); \ | |
| 45 | + efi_guid_t _guid; \ | |
| 46 | + const efi_guid_t * const _guid_p = \ | |
| 47 | + likely(__alignof__(guid) == sizeof(guid)) \ | |
| 48 | + ? guid \ | |
| 49 | + : &_guid; \ | |
| 50 | + \ | |
| 51 | + if (unlikely(__alignof__(guid) == sizeof(guid))) \ | |
| 52 | + memmove(&_guid, guid, sizeof(_guid)); \ | |
| 53 | + _rc = efi_guid_to_str(_guid_p, &_guidstr); \ | |
| 54 | if (_rc < 0) { \ | |
| 55 | efi_error("could not build %s GUID DP string", \ | |
| 56 | dp_type); \ |