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J . Lu" Cc: Kees Cook , Chris Kennelly , Eric Biederman , Shuah Khan , Muhammad Usama Anjum , John Hubbard , Fangrui Song , Andrew Morton , Yang Yingliang , Mike Rapoport , Rui Salvaterra , Victor Stinner , Jan Palus , Al Viro , Christian Brauner , Jan Kara , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH 2/3] binfmt_elf: Calculate total_size earlier Date: Wed, 8 May 2024 10:31:47 -0700 Message-Id: <20240508173149.677910-2-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240508172848.work.131-kees@kernel.org> References: <20240508172848.work.131-kees@kernel.org> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3041; i=keescook@chromium.org; h=from:subject; bh=Lh9sl0zFqUcR9HG/AVuIcrH791BNMQBsy4Th3x5GAR4=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBmO7cEHn0buAr/C675Nd09yTzC5UND2JGNtAzn6 7fAhDpYVyGJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZju3BAAKCRCJcvTf3G3A JpCtD/9LYmlihZG7ywOzTinHJzY1kGMdJPl8aorBC0w8BZYWZG2L5735ch2DLxaqLeucHcOdIzd j2P5KQxKEFi3VSlTEJgG/CHFTE/LdNWf8K4HNiSgIPRvftdZy0yfsLhEg6c1Bc5+jOOGN7Yw1Oz 6PcT0O2RfYEkFZSrUDCPgVVNxk1+jVVG6NCQXKg/g1beIDLLZRXDt/CujNa4YHVUpd/PYIZvsBI tyyKrW1A2QVx0+ktTAviklFaU/7UJYQBntwA7dredHuOtT/fqjgzVNTigROk/o3oX6LwbM3R/nS rpbycTLj73Gn4W97wBLGOx8O9yk/tSZARqYHaJgCzAFLUSp6KzKoPZby1r7csVaek1B3X8fP+8+ BkY4XLEZdalGU8cLbxI+PY/Qr9tF2wa2MjCxf53MHCqPc76J9sF8E993yLTDuBhej9jyYD3tQ8f szKoB0M+V2j30jykwU46I56obv/BNssOUb7HZuY3opJ8Mjr05I2VVwIQkqlyrX5+S5i6mvqRIui +CwG4y1jlqtzUR5IZywuhfiJ1adpU8sxNVbg6dRC8xSQ5BOBZyf262o/4gaFHzFjKf5iPULmnZ1 SvfgCjHzQ3eQ8HeL0WrvMnveAWiwczVNHiEsljH0SLouDc9W4fSSSyePhi6mu7GKCpxPtjxXxWH YPVMgoHtsFF9p3A== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 In preparation to support PT_LOAD with large p_align values on non-PT_INTERP ET_DYN executables (i.e. "static pie"), we'll need to use the total_size details earlier. Move this separately now to make the next patch more readable. As total_size and load_bias are currently calculated separately, this has no behavioral impact. Signed-off-by: Kees Cook --- fs/binfmt_elf.c | 52 +++++++++++++++++++++++++------------------------ 1 file changed, 27 insertions(+), 25 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 5397b552fbeb..56432e019d4e 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1061,7 +1061,34 @@ static int load_elf_binary(struct linux_binprm *bprm) * Header for ET_DYN binaries to calculate the * randomization (load_bias) for all the LOAD * Program Headers. + */ + + /* + * Calculate the entire size of the ELF mapping + * (total_size), used for the initial mapping, + * due to load_addr_set which is set to true later + * once the initial mapping is performed. + * + * Note that this is only sensible when the LOAD + * segments are contiguous (or overlapping). If + * used for LOADs that are far apart, this would + * cause the holes between LOADs to be mapped, + * running the risk of having the mapping fail, + * as it would be larger than the ELF file itself. * + * As a result, only ET_DYN does this, since + * some ET_EXEC (e.g. ia64) may have large virtual + * memory holes between LOADs. + * + */ + total_size = total_mapping_size(elf_phdata, + elf_ex->e_phnum); + if (!total_size) { + retval = -EINVAL; + goto out_free_dentry; + } + + /* * There are effectively two types of ET_DYN * binaries: programs (i.e. PIE: ET_DYN with INTERP) * and loaders (ET_DYN without INTERP, since they @@ -1102,31 +1129,6 @@ static int load_elf_binary(struct linux_binprm *bprm) * is then page aligned. */ load_bias = ELF_PAGESTART(load_bias - vaddr); - - /* - * Calculate the entire size of the ELF mapping - * (total_size), used for the initial mapping, - * due to load_addr_set which is set to true later - * once the initial mapping is performed. - * - * Note that this is only sensible when the LOAD - * segments are contiguous (or overlapping). If - * used for LOADs that are far apart, this would - * cause the holes between LOADs to be mapped, - * running the risk of having the mapping fail, - * as it would be larger than the ELF file itself. - * - * As a result, only ET_DYN does this, since - * some ET_EXEC (e.g. ia64) may have large virtual - * memory holes between LOADs. - * - */ - total_size = total_mapping_size(elf_phdata, - elf_ex->e_phnum); - if (!total_size) { - retval = -EINVAL; - goto out_free_dentry; - } } error = elf_load(bprm->file, load_bias + vaddr, elf_ppnt,