mirror of
https://github.com/dynup/kpatch
synced 2025-05-03 00:17:56 +00:00
4dee89269c
This adds support for shadow variables, which allow you to add new "shadow" fields to existing data structures. To allow patches to call the shadow functions in the core module, I had to add a funky hack to use --warn-unresolved-symbols when linking, which allows the patched vmlinux to link with the missing symbols. I also added greps to the log file to ensure that only unresolved symbols to kpatch_shadow_* are allowed. We can remove this hack once the core module gets moved into the kernel tree. Fixes #314.
73 lines
2.0 KiB
Diff
73 lines
2.0 KiB
Diff
Index: src/kernel/fork.c
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===================================================================
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--- src.orig/kernel/fork.c
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+++ src/kernel/fork.c
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@@ -1572,6 +1572,7 @@ struct task_struct *fork_idle(int cpu)
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* It copies the process, and if successful kick-starts
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* it and waits for it to finish using the VM if required.
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*/
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+#include "kpatch.h"
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long do_fork(unsigned long clone_flags,
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unsigned long stack_start,
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unsigned long stack_size,
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@@ -1622,6 +1623,13 @@ long do_fork(unsigned long clone_flags,
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if (!IS_ERR(p)) {
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struct completion vfork;
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struct pid *pid;
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+ int *newpid;
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+ static int ctr = 0;
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+
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+ newpid = kpatch_shadow_alloc(p, "newpid", sizeof(*newpid),
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+ GFP_KERNEL);
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+ if (newpid)
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+ *newpid = ctr++;
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trace_sched_process_fork(current, p);
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Index: src/fs/proc/array.c
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===================================================================
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--- src.orig/fs/proc/array.c
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+++ src/fs/proc/array.c
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@@ -337,13 +337,20 @@ static inline void task_seccomp(struct s
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#endif
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}
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+#include "kpatch.h"
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static inline void task_context_switch_counts(struct seq_file *m,
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struct task_struct *p)
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{
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+ int *newpid;
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+
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seq_printf(m, "voluntary_ctxt_switches:\t%lu\n"
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"nonvoluntary_ctxt_switches:\t%lu\n",
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p->nvcsw,
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p->nivcsw);
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+
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+ newpid = kpatch_shadow_get(p, "newpid");
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+ if (newpid)
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+ seq_printf(m, "newpid:\t%d\n", *newpid);
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}
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static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
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Index: src/kernel/exit.c
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===================================================================
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--- src.orig/kernel/exit.c
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+++ src/kernel/exit.c
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@@ -694,6 +694,7 @@ static void check_stack_usage(void)
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static inline void check_stack_usage(void) {}
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#endif
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+#include "kpatch.h"
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void do_exit(long code)
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{
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struct task_struct *tsk = current;
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@@ -790,6 +791,8 @@ void do_exit(long code)
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exit_task_work(tsk);
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exit_thread();
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+ kpatch_shadow_free(tsk, "newpid");
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+
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/*
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* Flush inherited counters to the parent - before the parent
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* gets woken up by child-exit notifications.
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