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Commit 762a327d authored by Jiri Olsa's avatar Jiri Olsa Committed by Sami Tolvanen
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UPSTREAM: fs/proc/kcore.c: Make bounce buffer global for read 



Next patch adds bounce buffer for ktext area, so it's
convenient to have single bounce buffer for both
vmalloc/module and ktext cases.

Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>

Bug: 31374226
Change-Id: I8f517354e6d12aed75ed4ae6c0a6adef0a1e61da
(cherry picked from commit f5beeb1851ea6f8cfcf2657f26cb24c0582b4945)
Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
parent 50bad62b

fs/proc/kcore.c

+14 −10
Original line number Diff line number Diff line
@@ -430,6 +430,7 @@ static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff) 
static ssize_t

read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)

{

	char *buf = file->private_data;

	ssize_t acc = 0;

	size_t size, tsz;

	size_t elf_buflen;
@@ -500,18 +501,10 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) 
			if (clear_user(buffer, tsz))

				return -EFAULT;

		} else if (is_vmalloc_or_module_addr((void *)start)) {

			char * elf_buf;



			elf_buf = kzalloc(tsz, GFP_KERNEL);

			if (!elf_buf)

				return -ENOMEM;

			vread(elf_buf, (char *)start, tsz);

			vread(buf, (char *)start, tsz);

			/* we have to zero-fill user buffer even if no read */

			if (copy_to_user(buffer, elf_buf, tsz)) {

				kfree(elf_buf);

			if (copy_to_user(buffer, buf, tsz))

				return -EFAULT;

			}

			kfree(elf_buf);

		} else {

			if (kern_addr_valid(start)) {

				unsigned long n;
@@ -549,6 +542,11 @@ static int open_kcore(struct inode *inode, struct file *filp) 
{

	if (!capable(CAP_SYS_RAWIO))

		return -EPERM;



	filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);

	if (!filp->private_data)

		return -ENOMEM;



	if (kcore_need_update)

		kcore_update_ram();

	if (i_size_read(inode) != proc_root_kcore->size) {
@@ -559,10 +557,16 @@ static int open_kcore(struct inode *inode, struct file *filp) 
	return 0;

}



static int release_kcore(struct inode *inode, struct file *file)

{

	kfree(file->private_data);

	return 0;

}



static const struct file_operations proc_kcore_operations = {

	.read		= read_kcore,

	.open		= open_kcore,

	.release	= release_kcore,

	.llseek		= default_llseek,

};