[PATCH v2 2/6] fs/proc/kcore: pfn_is_ram check only applies to KCORE_RAM
From: David Hildenbrand <hidden>
Date: 2021-05-14 17:23:33
Also in:
linux-fsdevel, linux-hyperv, lkml, virtualization
Subsystem:
filesystems (vfs and infrastructure), kcore, proc filesystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Omar Sandoval, Linus Torvalds
Let's resturcture the code, using switch-case, and checking pfn_is_ram() only when we are dealing with KCORE_RAM. Reviewed-by: Mike Rapoport <redacted> Signed-off-by: David Hildenbrand <redacted> --- fs/proc/kcore.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-)
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 09f77d3c6e15..ed6fbb3bd50c 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c@@ -483,25 +483,36 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) goto out; } m = NULL; /* skip the list anchor */ - } else if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) { - if (clear_user(buffer, tsz)) { - ret = -EFAULT; - goto out; - } - } else if (m->type == KCORE_VMALLOC) { + goto skip; + } + + switch (m->type) { + case KCORE_VMALLOC: vread(buf, (char *)start, tsz); /* we have to zero-fill user buffer even if no read */ if (copy_to_user(buffer, buf, tsz)) { ret = -EFAULT; goto out; } - } else if (m->type == KCORE_USER) { + break; + case KCORE_USER: /* User page is handled prior to normal kernel page: */ if (copy_to_user(buffer, (char *)start, tsz)) { ret = -EFAULT; goto out; } - } else { + break; + case KCORE_RAM: + if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) { + if (clear_user(buffer, tsz)) { + ret = -EFAULT; + goto out; + } + break; + } + fallthrough; + case KCORE_VMEMMAP: + case KCORE_TEXT: if (kern_addr_valid(start)) { /* * Using bounce buffer to bypass the
@@ -525,7 +536,15 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) goto out; } } + break; + default: + pr_warn_once("Unhandled KCORE type: %d\n", m->type); + if (clear_user(buffer, tsz)) { + ret = -EFAULT; + goto out; + } } +skip: buflen -= tsz; *fpos += tsz; buffer += tsz;
--
2.31.1