diff options
| author | Rusty Russell <rusty@rustcorp.com.au> | 2013-01-06 16:39:53 +0100 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2013-01-10 01:57:28 +0100 |
| commit | 98a683a78542d4ef62c5cdf8bb48304e52047587 (patch) | |
| tree | da1981d3591175539cc7baa010fa9b5931595f49 | |
| parent | 2038a83d74c2916ce6ccd7e1f1ec62985495f6f6 (diff) | |
| download | man-pages-98a683a78542d4ef62c5cdf8bb48304e52047587.tar.gz | |
init_module.2: Document finit_module() 'flags' argument
Document MODULE_INIT_IGNORE_MODVERSIONS and
MODULE_INIT_IGNORE_VERMAGIC. (Some edits by mtk.)
Reviewed-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
| -rw-r--r-- | man2/init_module.2 | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/man2/init_module.2 b/man2/init_module.2 index 10e71e2637..9d1098acf3 100644 --- a/man2/init_module.2 +++ b/man2/init_module.2 @@ -113,10 +113,39 @@ together zero or more of the following flags: .\" commit 2f3238aebedb243804f58d62d57244edec4149b2 .TP .B MODULE_INIT_IGNORE_MODVERSIONS -Ignore module versions. +Ignore symbol version hashes. .TP .B MODULE_INIT_IGNORE_VERMAGIC Ignore kernel version magic. +.PP +There are some safety checks built into a module to ensure that +it matches the kernel against which it is loaded. +.\" http://www.tldp.org/HOWTO/Module-HOWTO/basekerncompat.html +.\" is dated, but informative +These checks are recorded when the module is built and +verified when the module is loaded. +First, the module records a "vermagic" string containing +the kernel version number and prominent features (such as the CPU type). +Second, if the module was built with the +.B CONFIG_MODVERSIONS +configuration option enabled, +a version hash is recorded for each symbol the module uses. +This hash is based on the types of the arguments and return value +for the function named by the symbol. +In this case, the kernel version number within the +"vermagic" string is ignored, +as the symbol version hashes are assumed to be sufficiently reliable. + +Using the +.B MODULE_INIT_IGNORE_VERMAGIC +flag indicates that the "vermagic" string is to be ignored, and the +.B MODULE_INIT_IGNORE_MODVERSIONS +flag indicates that the symbol version hashes are to be ignored. +If the kernel is built to permit forced loading (i.e., configured with +.BR CONFIG_MODULE_FORCE_LOAD ), +then loading will continue, otherwise it will fail with +.B ENOEXEC +as expected for malformed modules. .SH "RETURN VALUE" On success, these system calls return 0. On error, \-1 is returned and |