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| author | Christoph Hellwig <hch@lst.de> | 2020-06-09 06:34:50 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-09 18:39:15 +0200 |
| commit | 98a23609b10364a51a1bb3688f8dd1cd1aa94a9a (patch) | |
| tree | 8cf32f92fccd8cd5264434d42fa68dcba4c2ab3c /mm/debug.c | |
| parent | maccess: remove strncpy_from_unsafe (diff) | |
| download | linux-98a23609b10364a51a1bb3688f8dd1cd1aa94a9a.tar.xz linux-98a23609b10364a51a1bb3688f8dd1cd1aa94a9a.zip | |
maccess: always use strict semantics for probe_kernel_read
Except for historical confusion in the kprobes/uprobes and bpf tracers,
which has been fixed now, there is no good reason to ever allow user
memory accesses from probe_kernel_read. Switch probe_kernel_read to only
read from kernel memory.
[akpm@linux-foundation.org: update it for "mm, dump_page(): do not crash with invalid mapping pointer"]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-17-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/debug.c')
| -rw-r--r-- | mm/debug.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/mm/debug.c b/mm/debug.c index f2ede2df585a..b5b1de8c71ac 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -120,9 +120,9 @@ void __dump_page(struct page *page, const char *reason) * mapping can be invalid pointer and we don't want to crash * accessing it, so probe everything depending on it carefully */ - if (probe_kernel_read_strict(&host, &mapping->host, - sizeof(struct inode *)) || - probe_kernel_read_strict(&a_ops, &mapping->a_ops, + if (probe_kernel_read(&host, &mapping->host, + sizeof(struct inode *)) || + probe_kernel_read(&a_ops, &mapping->a_ops, sizeof(struct address_space_operations *))) { pr_warn("failed to read mapping->host or a_ops, mapping not a valid kernel address?\n"); goto out_mapping; @@ -133,7 +133,7 @@ void __dump_page(struct page *page, const char *reason) goto out_mapping; } - if (probe_kernel_read_strict(&dentry_first, + if (probe_kernel_read(&dentry_first, &host->i_dentry.first, sizeof(struct hlist_node *))) { pr_warn("mapping->a_ops:%ps with invalid mapping->host inode address %px\n", a_ops, host); @@ -146,7 +146,7 @@ void __dump_page(struct page *page, const char *reason) } dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias); - if (probe_kernel_read_strict(&dentry, dentry_ptr, + if (probe_kernel_read(&dentry, dentry_ptr, sizeof(struct dentry))) { pr_warn("mapping->aops:%ps with invalid mapping->host->i_dentry.first %px\n", a_ops, dentry_ptr); |