[PATCH] module: Add more error message for failed kernel module loading
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STALE2230d
From: Qu Wenruo <hidden>
Date: 2020-08-29 11:14:50
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
When kernel module loading failed, user space only get one of the following error messages: - -ENOEXEC This is the most confusing one. From corrupted ELF header to bad WRITE|EXEC flags check introduced by in module_enforce_rwx_sections() all returns this error number. - -EPERM This is for blacklisted modules. But mod doesn't do extra explain on this error either. - -ENOMEM The only error which needs no explain. This means, if a user got "Exec format error" from modprobe, it provides no meaningful way for the user to debug, and will take extra time communicating to get extra info. So this patch will add extra error messages for -ENOEXEC and -EPERM errors, allowing user to do better debugging and reporting. Signed-off-by: Qu Wenruo <redacted> --- kernel/module.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index 1c5cff34d9f2..9f748c6eeb48 100644
--- a/kernel/module.c
+++ b/kernel/module.c@@ -2096,8 +2096,12 @@ static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, int i; for (i = 0; i < hdr->e_shnum; i++) { - if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) + if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) { + pr_err( + "Module %s section %d has invalid WRITE|EXEC flags\n", + mod->name, i); return -ENOEXEC; + } } return 0;
@@ -3825,8 +3829,10 @@ static int load_module(struct load_info *info, const char __user *uargs, char *after_dashes; err = elf_header_check(info); - if (err) + if (err) { + pr_err("Module has invalid ELF header\n"); goto free_copy; + } err = setup_load_info(info, flags); if (err)
@@ -3834,6 +3840,7 @@ static int load_module(struct load_info *info, const char __user *uargs, if (blacklisted(info->name)) { err = -EPERM; + pr_err("Module %s is blacklisted\n", info->name); goto free_copy; }
--
2.27.0