Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f1dad166e88a5ddca0acf8f11dea0e2bd92d8bf3
Commit: f1dad166e88a5ddca0acf8f11dea0e2bd92d8bf3
Parent: 092e1fdaf35126475aef0dc70f4a2ce4f2f43052
Author: Pavel Emelyanov <[EMAIL PROTECTED]>
AuthorDate: Tue Dec 4 23:45:24 2007 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Wed Dec 5 09:21:20 2007 -0800
Avoid potential NULL dereference in unregister_sysctl_table
register_sysctl_table() can return NULL sometimes, e.g. when kmalloc()
returns NULL or when sysctl check fails.
I've also noticed, that many (most?) code in the kernel doesn't check for
the return value from register_sysctl_table() and later simply calls the
unregister_sysctl_table() with potentially NULL argument.
This is unlikely on a common kernel configuration, but in case we're
dealing with modules and/or fault-injection support, there's a slight
possibility of an OOPS.
Changing all the users to check for return code from the registering does
not look like a good solution - there are too many code doing this and
failure in sysctl tables registration is not a good reason to abort module
loading (in most of the cases).
So I think, that we can just have this check in unregister_sysctl_table
just to avoid accidental OOPS-es (actually, the unregister_sysctl_table()
did exactly this, before the start_unregistering() appeared).
Signed-off-by: Pavel Emelyanov <[EMAIL PROTECTED]>
Cc: "Eric W. Biederman" <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
kernel/sysctl.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 0deed82..8ac5171 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1588,6 +1588,10 @@ struct ctl_table_header *register_sysctl_table(struct
ctl_table * table)
void unregister_sysctl_table(struct ctl_table_header * header)
{
might_sleep();
+
+ if (header == NULL)
+ return;
+
spin_lock(&sysctl_lock);
start_unregistering(header);
spin_unlock(&sysctl_lock);
-
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