Date: Tue, 25 Jun 2024 20:32:23 GMT From: Kyle Evans <kevans@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 3da568710fde - main - stand: module: unlink the entire tail when dependencies fail to load Message-ID: <202406252032.45PKWNbS026609@gitrepo.freebsd.org>
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The branch main has been updated by kevans: URL: https://cgit.FreeBSD.org/src/commit/?id=3da568710fde08251996c117b87bedb326dedb57 commit 3da568710fde08251996c117b87bedb326dedb57 Author: Kyle Evans <kevans@FreeBSD.org> AuthorDate: 2024-06-25 20:31:50 +0000 Commit: Kyle Evans <kevans@FreeBSD.org> CommitDate: 2024-06-25 20:32:08 +0000 stand: module: unlink the entire tail when dependencies fail to load Assume you have loader configured to load linux64, which has a dependency on both linux_common and mqueuefs but neither the kernel nor kernel config in question have the mqueuefs module included. When the load command for linux64 fails to find mqueuefs, it will free both linux64 and linux_common as they were loaded first, but only linux64 gets removed from the module list. As a result, future traversals hit an easy use-after-free with linux_common. Fix it so that we unlink the entire tail of the list. Anything after the initially loaded module is, by definition, a dependency on the loaded module while we're still in the load command, so we can just discard the entire tail. If linux_common were loaded before linux64, it should not move to a position during this load where it would suddenly be missing from the view presented to the kernel. Reported by: philip Reviewed by: imp, philip, tsoome MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D45731 --- stand/common/module.c | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) diff --git a/stand/common/module.c b/stand/common/module.c index 832a8eb4988d..29228f0de22a 100644 --- a/stand/common/module.c +++ b/stand/common/module.c @@ -64,6 +64,7 @@ static char *mod_searchmodule(char *name, struct mod_depend *verinfo); static char * mod_searchmodule_pnpinfo(const char *bus, const char *pnpinfo); static void file_insert_tail(struct preloaded_file *mp); static void file_remove(struct preloaded_file *fp); +static void file_remove_tail(struct preloaded_file *fp); struct file_metadata* metadata_next(struct file_metadata *base_mp, int type); static void moduledir_readhints(struct moduledir *mdp); static void moduledir_rebuild(void); @@ -876,7 +877,7 @@ mod_loadkld(const char *kldname, int argc, char *argv[]) file_insert_tail(fp); /* Add to the list of loaded files */ if (file_load_dependencies(fp) != 0) { err = ENOENT; - file_remove(fp); + file_remove_tail(fp); loadaddr = loadaddr_saved; fp = NULL; break; @@ -1637,25 +1638,45 @@ file_insert_tail(struct preloaded_file *fp) * Remove module from the chain */ static void -file_remove(struct preloaded_file *fp) +file_remove_impl(struct preloaded_file *fp, bool keep_tail) { - struct preloaded_file *cm; + struct preloaded_file *cm, *next; if (preloaded_files == NULL) return; + if (keep_tail) + next = fp->f_next; + else + next = NULL; + if (preloaded_files == fp) { - preloaded_files = fp->f_next; + preloaded_files = next; return; } + for (cm = preloaded_files; cm->f_next != NULL; cm = cm->f_next) { if (cm->f_next == fp) { - cm->f_next = fp->f_next; + cm->f_next = next; return; } } } +static void +file_remove(struct preloaded_file *fp) +{ + + file_remove_impl(fp, true); +} + +static void +file_remove_tail(struct preloaded_file *fp) +{ + + file_remove_impl(fp, false); +} + static char * moduledir_fullpath(struct moduledir *mdp, const char *fname) {
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