From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794061164; b=vzMaOeBe1LDTx+JF8emu+LmfnPN8qgfRLq3Ri2pmi7YM+oYZg9Q3fJYNru24JMUd1Vj7 Tx9Y/5/LxlvsNqjs9ydazGW9KTR0FBtgJxC960r96Kz0ltBlQRusrVtTnkUgQTfjoPhQA p4EMChNwrlvhA/VWfVAUF/NeCCVEoNNfB8+8kS42lAUXxEbgv8MxEHJU7ivUEjPSLbIbC VwgYmq+oqOfA02QlM2dh2m+R/58v7QGiLsyFV3R4lprGr7EACk5pWCzHHlIfbFqu0XRmo XvJ8+J8Q4dUyy/aXsjJIU5SxedaA9exr9tXJSw/XA+mhnF0DrDZxa/o0ne/8sLCljQg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794061164; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=v/Ts0D0eBc97SpxQN4xcRCzAK157gtN+OxgX0aXb6W0=; b=tV8S12UmsZR5a4n9qtOPkZ3rqrws1EHWMH1UjCtJN6yfvyJIVj6zAfFYUd1cA+MWXz5f HFtPJCz/6Cp2jdAo9Yy4T8IarprghLRaPtTxe6MYeKyxBD+9hBs+LFJ6ku7H4o0qoweJ6 Z8kv3IwjOzwwPeQLiVCvXTiSe1+h1z0DHDNl/oZBy3Y3iFEjPEmcSrULejfm1X2LtlxLK UXVfSJKHwnQqQxWrZUkb6StXOEYclF53uev8/YNJf+sjVt9+KkzesZQizAuT1qphoD2xZ oM6V93Ad2oXCQ5lYnqCpuYECbCvPsB0MFUuWFb9IqpoRzxognlKn+5QWXE+t79VDTcA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=AOefdpDL; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81EDF606EEBE; Sat, 7 Nov 2026 14:19:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=AOefdpDL Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D3A11F0089F; Sat, 7 Nov 2026 14:19:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794061164; bh=v/Ts0D0eBc97SpxQN4xcRCzAK157gtN+OxgX0aXb6W0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=AOefdpDLME+2Gqf7Nk0OVuLrsx0E0JocUPT0A6xFnAyYURS9eEl13Nh0StnaAsJxn iQ04e8JsBo8/kEOPQNQLv//C/b9llEpjps/38QO35XTA4IjWb6gr8OOE75VTg2IWFY MNepphCCsl6cQ4TBJXS91VxImZASSCy63L0kdcV0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Matthew Maurer , Sami Tolvanen , Luis Chamberlain , Sasha Levin Subject: [PATCH 6.12 0470/1536] module: Factor out elf_validity_cache_index_mod Date: Sat, 7 Nov 2026 08:41:26 -0500 Message-ID: <20261107135010.714348255@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthew Maurer [ Upstream commit 0be41a9367d1fbb16b4b57d81082341af114bad7 ] Centralize .gnu.linkonce.this_module detection and property validation. Signed-off-by: Matthew Maurer Reviewed-by: Sami Tolvanen Signed-off-by: Luis Chamberlain Stable-dep-of: 9a5ff4568932 ("module: validate string table section types") Signed-off-by: Sasha Levin --- kernel/module/main.c | 129 ++++++++++++++++++++++--------------------- 1 file changed, 67 insertions(+), 62 deletions(-) diff --git a/kernel/module/main.c b/kernel/module/main.c index 87ce807015b30..d77bb2cf7a0e6 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -1928,6 +1928,68 @@ static int elf_validity_cache_index_info(struct load_info *info) return 0; } +/** + * elf_validity_cache_index_mod() - Validates and caches this_module section + * @info: Load info to cache this_module on. + * Must have &load_info->sechdrs and &load_info->secstrings populated + * + * The ".gnu.linkonce.this_module" ELF section is special. It is what modpost + * uses to refer to __this_module and let's use rely on THIS_MODULE to point + * to &__this_module properly. The kernel's modpost declares it on each + * modules's *.mod.c file. If the struct module of the kernel changes a full + * kernel rebuild is required. + * + * We have a few expectations for this special section, this function + * validates all this for us: + * + * * The section has contents + * * The section is unique + * * We expect the kernel to always have to allocate it: SHF_ALLOC + * * The section size must match the kernel's run time's struct module + * size + * + * If all checks pass, the index will be cached in &load_info->index.mod + * + * Return: %0 on validation success, %-ENOEXEC on failure + */ +static int elf_validity_cache_index_mod(struct load_info *info) +{ + Elf_Shdr *shdr; + int mod_idx; + + mod_idx = find_any_unique_sec(info, ".gnu.linkonce.this_module"); + if (mod_idx <= 0) { + pr_err("module %s: Exactly one .gnu.linkonce.this_module section must exist.\n", + info->name ?: "(missing .modinfo section or name field)"); + return -ENOEXEC; + } + + shdr = &info->sechdrs[mod_idx]; + + if (shdr->sh_type == SHT_NOBITS) { + pr_err("module %s: .gnu.linkonce.this_module section must have a size set\n", + info->name ?: "(missing .modinfo section or name field)"); + return -ENOEXEC; + } + + if (!(shdr->sh_flags & SHF_ALLOC)) { + pr_err("module %s: .gnu.linkonce.this_module must occupy memory during process execution\n", + info->name ?: "(missing .modinfo section or name field)"); + return -ENOEXEC; + } + + if (shdr->sh_size != sizeof(struct module)) { + pr_err("module %s: .gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n", + info->name ?: "(missing .modinfo section or name field)"); + return -ENOEXEC; + } + + info->index.mod = mod_idx; + + return 0; +} + + /* * Check userspace passed ELF module against our expectations, and cache * useful variables for further processing as we go. @@ -1953,7 +2015,6 @@ static int elf_validity_cache_copy(struct load_info *info, int flags) unsigned int i; Elf_Shdr *shdr; int err; - unsigned int num_mod_secs = 0, mod_idx; unsigned int num_sym_secs = 0, sym_idx; err = elf_validity_cache_sechdrs(info); @@ -1963,16 +2024,15 @@ static int elf_validity_cache_copy(struct load_info *info, int flags) if (err < 0) return err; err = elf_validity_cache_index_info(info); + if (err < 0) + return err; + err = elf_validity_cache_index_mod(info); if (err < 0) return err; for (i = 1; i < info->hdr->e_shnum; i++) { shdr = &info->sechdrs[i]; - switch (shdr->sh_type) { - case SHT_NULL: - case SHT_NOBITS: - continue; - case SHT_SYMTAB: + if (shdr->sh_type == SHT_SYMTAB) { if (shdr->sh_link == SHN_UNDEF || shdr->sh_link >= info->hdr->e_shnum) { pr_err("Invalid ELF sh_link!=SHN_UNDEF(%d) or (sh_link(%d) >= hdr->e_shnum(%d)\n", @@ -1982,14 +2042,6 @@ static int elf_validity_cache_copy(struct load_info *info, int flags) } num_sym_secs++; sym_idx = i; - fallthrough; - default: - if (strcmp(info->secstrings + shdr->sh_name, - ".gnu.linkonce.this_module") == 0) { - num_mod_secs++; - mod_idx = i; - } - break; } } @@ -2005,55 +2057,8 @@ static int elf_validity_cache_copy(struct load_info *info, int flags) info->index.str = shdr->sh_link; info->strtab = (char *)info->hdr + info->sechdrs[info->index.str].sh_offset; - /* - * The ".gnu.linkonce.this_module" ELF section is special. It is - * what modpost uses to refer to __this_module and let's use rely - * on THIS_MODULE to point to &__this_module properly. The kernel's - * modpost declares it on each modules's *.mod.c file. If the struct - * module of the kernel changes a full kernel rebuild is required. - * - * We have a few expectaions for this special section, the following - * code validates all this for us: - * - * o Only one section must exist - * o We expect the kernel to always have to allocate it: SHF_ALLOC - * o The section size must match the kernel's run time's struct module - * size - */ - if (num_mod_secs != 1) { - pr_err("module %s: Only one .gnu.linkonce.this_module section must exist.\n", - info->name ?: "(missing .modinfo section or name field)"); - goto no_exec; - } - - shdr = &info->sechdrs[mod_idx]; - - /* - * This is already implied on the switch above, however let's be - * pedantic about it. - */ - if (shdr->sh_type == SHT_NOBITS) { - pr_err("module %s: .gnu.linkonce.this_module section must have a size set\n", - info->name ?: "(missing .modinfo section or name field)"); - goto no_exec; - } - - if (!(shdr->sh_flags & SHF_ALLOC)) { - pr_err("module %s: .gnu.linkonce.this_module must occupy memory during process execution\n", - info->name ?: "(missing .modinfo section or name field)"); - goto no_exec; - } - - if (shdr->sh_size != sizeof(struct module)) { - pr_err("module %s: .gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n", - info->name ?: "(missing .modinfo section or name field)"); - goto no_exec; - } - - info->index.mod = mod_idx; - /* This is temporary: point mod into copy of data. */ - info->mod = (void *)info->hdr + shdr->sh_offset; + info->mod = (void *)info->hdr + info->sechdrs[info->index.mod].sh_offset; /* * If we didn't load the .modinfo 'name' field earlier, fall back to -- 2.53.0