[RFC PATCH 02/14] fs/proc/vmcore: Update copy_oldmem_page_encrypted() for user buffer
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STALE1769d
From: Amit Daniel Kachhap <hidden>
Date: 2021-12-03 10:42:59
Also in:
kexec, linux-fsdevel
Subsystem:
filesystems (vfs and infrastructure), kdump, proc filesystem, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Alexander Viro, Christian Brauner, Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
The exported interface copy_oldmem_page_encrypted() passes user pointer without __user annotation and does unnecessary user/kernel pointer conversions during the pointer propagation. Hence it is modified to have a new parameter for user pointer. The other similar interface copy_oldmem_page() will be updated in the subsequent patches. x86_64 crash dump is also modified to use this modified interface. No functionality change intended. Cc: Thomas Gleixner <redacted> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Young <redacted> Cc: Baoquan He <redacted> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: x86 <x86@kernel.org> Cc: kexec <redacted> Cc: linux-fsdevel <redacted> Signed-off-by: Amit Daniel Kachhap <redacted> --- arch/x86/kernel/crash_dump_64.c | 12 +++++++++--- fs/proc/vmcore.c | 24 +++++++++++------------- include/linux/crash_dump.h | 6 +++--- 3 files changed, 23 insertions(+), 19 deletions(-)
diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 6433513ef43a..99cd505628fa 100644
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c@@ -66,10 +66,16 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, * memory with the encryption mask set to accommodate kdump on SME-enabled * machines. */ -ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char __user *ubuf, + char *kbuf, size_t csize, + unsigned long offset) { - return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true); + if (ubuf) + return __copy_oldmem_page(pfn, (__force char *)ubuf, csize, + offset, 1, true); + else + return __copy_oldmem_page(pfn, kbuf, csize, + offset, 0, true); } ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 39b4353bd37c..fa4492ef6124 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c@@ -168,16 +168,10 @@ ssize_t read_from_oldmem(char __user *ubuf, char *kbuf, size_t count, else if (clear_user(ubuf, nr_bytes)) tmp = -EFAULT; } else { - if (encrypted && ubuf) - tmp = copy_oldmem_page_encrypted(pfn, - (__force char *)ubuf, - nr_bytes, - offset, 1); - else if (encrypted && kbuf) - tmp = copy_oldmem_page_encrypted(pfn, - kbuf, - nr_bytes, - offset, 0); + if (encrypted) + tmp = copy_oldmem_page_encrypted(pfn, ubuf, + kbuf, nr_bytes, + offset); else if (ubuf) tmp = copy_oldmem_page(pfn, (__force char *)ubuf, nr_bytes, offset, 1);
@@ -247,10 +241,14 @@ int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma, * Architectures which support memory encryption override this. */ ssize_t __weak -copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +copy_oldmem_page_encrypted(unsigned long pfn, char __user *ubuf, char *kbuf, + size_t csize, unsigned long offset) { - return copy_oldmem_page(pfn, buf, csize, offset, userbuf); + if (ubuf) + return copy_oldmem_page(pfn, (__force char *)ubuf, csize, + offset, 1); + else + return copy_oldmem_page(pfn, kbuf, csize, offset, 0); } /*
diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index eb0ed423ccc8..36a7f08f4ad2 100644
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h@@ -26,9 +26,9 @@ extern int remap_oldmem_pfn_range(struct vm_area_struct *vma, extern ssize_t copy_oldmem_page(unsigned long, char *, size_t, unsigned long, int); -extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, - int userbuf); +extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn, + char __user *ubuf, char *kbuf, + size_t csize, unsigned long offset); void vmcore_cleanup(void);
--
2.17.1