diff options
Diffstat (limited to 'kernel/module/main.c')
| -rw-r--r-- | kernel/module/main.c | 62 |
1 files changed, 53 insertions, 9 deletions
diff --git a/kernel/module/main.c b/kernel/module/main.c index cf097ffe6a4a..e1a9dd51c036 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2,6 +2,7 @@ /* * Copyright (C) 2002 Richard Henderson * Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM. + * Copyright (C) 2023 Luis Chamberlain <mcgrof@kernel.org> */ #define INCLUDE_VERMAGIC @@ -1656,6 +1657,7 @@ static int elf_validity_check(struct load_info *info) unsigned int i; Elf_Shdr *shdr, *strhdr; int err; + unsigned int num_mod_secs = 0, mod_idx; if (info->len < sizeof(*(info->hdr))) { pr_err("Invalid ELF header len %lu\n", info->len); @@ -1767,6 +1769,11 @@ static int elf_validity_check(struct load_info *info) i, shdr->sh_type); return err; } + if (strcmp(info->secstrings + shdr->sh_name, + ".gnu.linkonce.this_module") == 0) { + num_mod_secs++; + mod_idx = i; + } if (shdr->sh_flags & SHF_ALLOC) { if (shdr->sh_name >= strhdr->sh_size) { @@ -1779,6 +1786,52 @@ static int elf_validity_check(struct load_info *info) } } + /* + * 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("Only one .gnu.linkonce.this_module section must exist.\n"); + 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(".gnu.linkonce.this_module section must have a size set\n"); + goto no_exec; + } + + if (!(shdr->sh_flags & SHF_ALLOC)) { + pr_err(".gnu.linkonce.this_module must occupy memory during process execution\n"); + goto no_exec; + } + + if (shdr->sh_size != sizeof(struct module)) { + pr_err(".gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n"); + 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; + return 0; no_exec: @@ -1925,15 +1978,6 @@ static int setup_load_info(struct load_info *info, int flags) return -ENOEXEC; } - info->index.mod = find_sec(info, ".gnu.linkonce.this_module"); - if (!info->index.mod) { - pr_warn("%s: No module found in object\n", - info->name ?: "(missing .modinfo section or name field)"); - return -ENOEXEC; - } - /* This is temporary: point mod into copy of data. */ - 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 * on-disk struct mod 'name' field. |