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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id s26-20020aa78d5a000000b00672ea40b8a9sm14427552pfe.170.2023.09.28.20.24.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Sep 2023 20:24:39 -0700 (PDT) From: Kees Cook To: Eric Biederman Cc: Kees Cook , Alexander Viro , Christian Brauner , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Sebastian Ott , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , Pedro Falcato , Andrew Morton , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH v4 2/6] binfmt_elf: elf_bss no longer used by load_elf_binary() Date: Thu, 28 Sep 2023 20:24:30 -0700 Message-Id: <20230929032435.2391507-2-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230929031716.it.155-kees@kernel.org> References: <20230929031716.it.155-kees@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1738; i=keescook@chromium.org; h=from:subject; bh=G8gKivjP+bPsGdacm75CduzZVarN6sAt0dfrtCVUjtY=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlFkNx2BuLhX7iIAkgIu+LW3P3r4pxnZlwRaDRf vA/0AICBj2JAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZRZDcQAKCRCJcvTf3G3A JpKyD/9/zd7E+5U1dJPLc6FAk+4qelFfCB75a77Kwxx0x/dnFrrOEedqqpaOK3ve3TybifJrVjE h8wTDDoxua66DT705EB1I4t9hKVj7ivb1dRVQdU3WehX4HAJzhPWJ7EtDjtX4AeM5D+Hf7hDpz4 hfwpwEYxXXAs73zeYWM19Na85lFwu6nSgf/ttA5F2ewH+beQAvHkMQN6gO9tp95OrFyS1MZdXBI NrkU9qg/ruk3uLO2OsVV6oDaLOu79M+4Kf6narATryoLsN4PLTkC8vQrd2qtvfiFgrJMPpbfCn8 mEteP/5U+mKLFaCYdxhauFlCzaPVAwvY9GsSaOxsm+ilLLoz76BgaZJ3mTlmC1hryS1DfX5TNYm BmEtiulolRPfz4jsO8ynBLlG9W3OMzNzN8tAFwtRv5C9pp0Y+Fp2Q4+kBwt72QGCQLH4GAe0o9t m4EhUZsGXS3t3VJlwU/3NoxBNO9bz5DuQRp5K6qTCwsnbFMQXMIL3xR1Vd0jwfPPrscAtd+3IlT pbesK8GLRSzYSy4YOE92dGY+Av5QlXCA+DMcppAI/si2TTqnM19+SkKDASB7HwxP2YQiCADAV3U 67MufnT9YBLfq2RWMu1o2nR3+x4f5uWbDtEvSPRE7Ki8QD8I5Ldh64XqqxhTjKdmqEPIl7TvgC2 QoH6u6C/JkEFAwQ== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" With the BSS handled generically via the new filesz/memsz mismatch handling logic in elf_load(), elf_bss no longer needs to be tracked. Drop the variable. Cc: Eric Biederman Cc: Alexander Viro Cc: Christian Brauner Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Suggested-by: Eric Biederman Signed-off-by: Kees Cook --- fs/binfmt_elf.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 2a615f476e44..0214d5a949fc 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -854,7 +854,7 @@ static int load_elf_binary(struct linux_binprm *bprm) unsigned long error; struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata =3D NULL; struct elf_phdr *elf_property_phdata =3D NULL; - unsigned long elf_bss, elf_brk; + unsigned long elf_brk; int retval, i; unsigned long elf_entry; unsigned long e_entry; @@ -1045,7 +1045,6 @@ static int load_elf_binary(struct linux_binprm *bprm) if (retval < 0) goto out_free_dentry; =20 - elf_bss =3D 0; elf_brk =3D 0; =20 start_code =3D ~0UL; @@ -1208,8 +1207,6 @@ static int load_elf_binary(struct linux_binprm *bprm) =20 k =3D elf_ppnt->p_vaddr + elf_ppnt->p_filesz; =20 - if (k > elf_bss) - elf_bss =3D k; if ((elf_ppnt->p_flags & PF_X) && end_code < k) end_code =3D k; if (end_data < k) @@ -1221,7 +1218,6 @@ static int load_elf_binary(struct linux_binprm *bprm) =20 e_entry =3D elf_ex->e_entry + load_bias; phdr_addr +=3D load_bias; - elf_bss +=3D load_bias; elf_brk +=3D load_bias; start_code +=3D load_bias; end_code +=3D load_bias; --=20 2.34.1