| Message ID | 20180919065144.25010-9-ard.biesheuvel@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | add support for relative references in jump tables | expand |
Hi, On Tue, Sep 18, 2018 at 11:51:43PM -0700, Ard Biesheuvel wrote: > The __jump_table sections emitted into the core kernel and into > each module consist of statically initialized references into > other parts of the code, and with the exception of entries that > point into init code, which are defused at post-init time, these > data structures are never modified. > > So let's move them into the ro_after_init section, to prevent them > from being corrupted inadvertently by buggy code, or deliberately > by an attacker. > > Reviewed-by: Kees Cook <keescook@chromium.org> > Acked-by: Jessica Yu <jeyu@kernel.org> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> This patch results in build failures when trying to build s390 images. s390-linux-ld:./arch/s390/kernel/vmlinux.lds:41: syntax error Bisect log is attached. Guenter --- # bad: [4794a36bf08dfa89fe636e5080db9d8350e255dd] Add linux-next specific files for 20180928 # good: [6bf4ca7fbc85d80446ac01c0d1d77db4d91a6d84] Linux 4.19-rc5 git bisect start 'HEAD' 'v4.19-rc5' # good: [d5b0eb1f139e00e8fd18329d446688b19859755e] Merge remote-tracking branch 'crypto/master' git bisect good d5b0eb1f139e00e8fd18329d446688b19859755e # bad: [d9c3085241c16503e659c2d7f43578f297bf30dc] Merge remote-tracking branch 'tip/auto-latest' git bisect bad d9c3085241c16503e659c2d7f43578f297bf30dc # good: [db9825c95498280718c4687fcf712016f5b6f5f6] Merge tag 'drm-intel-next-2018-09-21' of git://anongit.freedesktop.org/drm/drm-intel into drm-next git bisect good db9825c95498280718c4687fcf712016f5b6f5f6 # good: [b22777af06f425911c85d8a2c6b4ed929d4e829f] Merge remote-tracking branch 'mmc/next' git bisect good b22777af06f425911c85d8a2c6b4ed929d4e829f # bad: [14cb9d65a396c00eb44e1af967f1c393593f3a4c] Merge branch 'x86/microcode' git bisect bad 14cb9d65a396c00eb44e1af967f1c393593f3a4c # good: [c6b5da093a8ba740b71dd0052f3846016986fd21] perf intel-pt: Add decoder flags for trace begin / end git bisect good c6b5da093a8ba740b71dd0052f3846016986fd21 # bad: [441a6b5c97e0136b416a2c12a0c361423a47c717] Merge branch 'sched/core' git bisect bad 441a6b5c97e0136b416a2c12a0c361423a47c717 # bad: [d43b23bddade094b1a64a087bc5626a065c3c6e5] Merge branch 'locking/core' git bisect bad d43b23bddade094b1a64a087bc5626a065c3c6e5 # good: [fa70f0d2ce96a892b38fbbaa60584af536f21f97] Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into efi/core git bisect good fa70f0d2ce96a892b38fbbaa60584af536f21f97 # bad: [ecf89ab872e94999366834689198c436c06ab68f] Merge branch 'core/core' git bisect bad ecf89ab872e94999366834689198c436c06ab68f # good: [9fc0f798ab8a6c042d811e45086260eb59be45c1] x86/jump_label: Switch to jump_entry accessors git bisect good 9fc0f798ab8a6c042d811e45086260eb59be45c1 # good: [19483677684b6ca01606f58503cb79cdfbbc7c72] jump_label: Annotate entries that operate on __init code earlier git bisect good 19483677684b6ca01606f58503cb79cdfbbc7c72 # bad: [13ddb52c165ba47d153b7b040931a5cbe9220866] s390/jump_label: Switch to relative references git bisect bad 13ddb52c165ba47d153b7b040931a5cbe9220866 # bad: [e872267b8bcbb179e21ccc7118f258873d6e7a59] jump_table: Move entries into ro_after_init region git bisect bad e872267b8bcbb179e21ccc7118f258873d6e7a59 # first bad commit: [e872267b8bcbb179e21ccc7118f258873d6e7a59] jump_table: Move entries into ro_after_init region
diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index b43f8d33a369..4042bbf3f9ad 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -66,6 +66,7 @@ SECTIONS *(.data..ro_after_init) } EXCEPTION_TABLE(16) + JUMP_TABLE_DATA . = ALIGN(PAGE_SIZE); __end_ro_after_init = .; diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 7b75ff6e2fce..f09ee3c544bc 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -253,10 +253,6 @@ STRUCT_ALIGN(); \ *(__tracepoints) \ /* implement dynamic printk debug */ \ - . = ALIGN(8); \ - __start___jump_table = .; \ - KEEP(*(__jump_table)) \ - __stop___jump_table = .; \ . = ALIGN(8); \ __start___verbose = .; \ KEEP(*(__verbose)) \ @@ -300,6 +296,12 @@ . = __start_init_task + THREAD_SIZE; \ __end_init_task = .; +#define JUMP_TABLE_DATA \ + . = ALIGN(8); \ + __start___jump_table = .; \ + KEEP(*(__jump_table)) \ + __stop___jump_table = .; + /* * Allow architectures to handle ro_after_init data on their * own by defining an empty RO_AFTER_INIT_DATA. @@ -308,6 +310,7 @@ #define RO_AFTER_INIT_DATA \ __start_ro_after_init = .; \ *(.data..ro_after_init) \ + JUMP_TABLE_DATA \ __end_ro_after_init = .; #endif diff --git a/kernel/module.c b/kernel/module.c index 6746c85511fe..49a405891587 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3315,6 +3315,15 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set. */ ndx = find_sec(info, ".data..ro_after_init"); + if (ndx) + info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT; + /* + * Mark the __jump_table section as ro_after_init as well: these data + * structures are never modified, with the exception of entries that + * refer to code in the __init section, which are annotated as such + * at module load time. + */ + ndx = find_sec(info, "__jump_table"); if (ndx) info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;