The patch titled
Subject: kexec: move segment verification code in a separate function
has been added to the -mm tree. Its filename is
kexec-move-segment-verification-code-in-a-separate-function.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kexec-move-segment-verification-code-in-a-separate-function.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kexec-move-segment-verification-code-in-a-separate-function.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Vivek Goyal <vgoyal@xxxxxxxxxx>
Subject: kexec: move segment verification code in a separate function
Previously do_kimage_alloc() will allocate a kimage structure, copy
segment list from user space and then do the segment list sanity
verification.
Break down this function in 3 parts. do_kimage_alloc_init() to do actual
allocation and basic initialization of kimage structure.
copy_user_segment_list() to copy segment list from user space and
sanity_check_segment_list() to verify the sanity of segment list as passed
by user space.
In later patches, I need to only allocate kimage and not copy segment list
from user space. So breaking down in smaller functions enables re-use of
code at other places.
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <greg@xxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: WANG Chao <chaowang@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kexec.c | 182 +++++++++++++++++++++++++----------------------
1 file changed, 100 insertions(+), 82 deletions(-)
diff -puN kernel/kexec.c~kexec-move-segment-verification-code-in-a-separate-function kernel/kexec.c
--- a/kernel/kexec.c~kexec-move-segment-verification-code-in-a-separate-function
+++ a/kernel/kexec.c
@@ -124,45 +124,27 @@ static struct page *kimage_alloc_page(st
gfp_t gfp_mask,
unsigned long dest);
-static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
- unsigned long nr_segments,
- struct kexec_segment __user *segments)
+static int copy_user_segment_list(struct kimage *image,
+ unsigned long nr_segments,
+ struct kexec_segment __user *segments)
{
+ int ret;
size_t segment_bytes;
- struct kimage *image;
- unsigned long i;
- int result;
-
- /* Allocate a controlling structure */
- result = -ENOMEM;
- image = kzalloc(sizeof(*image), GFP_KERNEL);
- if (!image)
- goto out;
-
- image->head = 0;
- image->entry = &image->head;
- image->last_entry = &image->head;
- image->control_page = ~0; /* By default this does not apply */
- image->start = entry;
- image->type = KEXEC_TYPE_DEFAULT;
-
- /* Initialize the list of control pages */
- INIT_LIST_HEAD(&image->control_pages);
-
- /* Initialize the list of destination pages */
- INIT_LIST_HEAD(&image->dest_pages);
-
- /* Initialize the list of unusable pages */
- INIT_LIST_HEAD(&image->unusable_pages);
/* Read in the segments */
image->nr_segments = nr_segments;
segment_bytes = nr_segments * sizeof(*segments);
- result = copy_from_user(image->segment, segments, segment_bytes);
- if (result) {
- result = -EFAULT;
- goto out;
- }
+ ret = copy_from_user(image->segment, segments, segment_bytes);
+ if (ret)
+ ret = -EFAULT;
+
+ return ret;
+}
+
+static int sanity_check_segment_list(struct kimage *image)
+{
+ int result, i;
+ unsigned long nr_segments = image->nr_segments;
/*
* Verify we have good destination addresses. The caller is
@@ -184,9 +166,9 @@ static int do_kimage_alloc(struct kimage
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz;
if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
- goto out;
+ return result;
if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
- goto out;
+ return result;
}
/* Verify our destination addresses do not overlap.
@@ -207,7 +189,7 @@ static int do_kimage_alloc(struct kimage
pend = pstart + image->segment[j].memsz;
/* Do the segments overlap ? */
if ((mend > pstart) && (mstart < pend))
- goto out;
+ return result;
}
}
@@ -219,18 +201,61 @@ static int do_kimage_alloc(struct kimage
result = -EINVAL;
for (i = 0; i < nr_segments; i++) {
if (image->segment[i].bufsz > image->segment[i].memsz)
- goto out;
+ return result;
+ }
+
+ /*
+ * Verify we have good destination addresses. Normally
+ * the caller is responsible for making certain we don't
+ * attempt to load the new image into invalid or reserved
+ * areas of RAM. But crash kernels are preloaded into a
+ * reserved area of ram. We must ensure the addresses
+ * are in the reserved area otherwise preloading the
+ * kernel could corrupt things.
+ */
+
+ if (image->type == KEXEC_TYPE_CRASH) {
+ result = -EADDRNOTAVAIL;
+ for (i = 0; i < nr_segments; i++) {
+ unsigned long mstart, mend;
+
+ mstart = image->segment[i].mem;
+ mend = mstart + image->segment[i].memsz - 1;
+ /* Ensure we are within the crash kernel limits */
+ if ((mstart < crashk_res.start) ||
+ (mend > crashk_res.end))
+ return result;
+ }
}
- result = 0;
-out:
- if (result == 0)
- *rimage = image;
- else
- kfree(image);
+ return 0;
+}
- return result;
+static struct kimage *do_kimage_alloc_init(void)
+{
+ struct kimage *image;
+ /* Allocate a controlling structure */
+ image = kzalloc(sizeof(*image), GFP_KERNEL);
+ if (!image)
+ return NULL;
+
+ image->head = 0;
+ image->entry = &image->head;
+ image->last_entry = &image->head;
+ image->control_page = ~0; /* By default this does not apply */
+ image->type = KEXEC_TYPE_DEFAULT;
+
+ /* Initialize the list of control pages */
+ INIT_LIST_HEAD(&image->control_pages);
+
+ /* Initialize the list of destination pages */
+ INIT_LIST_HEAD(&image->dest_pages);
+
+ /* Initialize the list of unusable pages */
+ INIT_LIST_HEAD(&image->unusable_pages);
+
+ return image;
}
static void kimage_free_page_list(struct list_head *list);
@@ -243,10 +268,19 @@ static int kimage_normal_alloc(struct ki
struct kimage *image;
/* Allocate and initialize a controlling structure */
- image = NULL;
- result = do_kimage_alloc(&image, entry, nr_segments, segments);
+ image = do_kimage_alloc_init();
+ if (!image)
+ return -ENOMEM;
+
+ image->start = entry;
+
+ result = copy_user_segment_list(image, nr_segments, segments);
+ if (result)
+ goto out_free_image;
+
+ result = sanity_check_segment_list(image);
if (result)
- goto out;
+ goto out_free_image;
/*
* Find a location for the control code buffer, and add it
@@ -258,22 +292,21 @@ static int kimage_normal_alloc(struct ki
get_order(KEXEC_CONTROL_PAGE_SIZE));
if (!image->control_code_page) {
pr_err("Could not allocate control_code_buffer\n");
- goto out_free;
+ goto out_free_image;
}
image->swap_page = kimage_alloc_control_pages(image, 0);
if (!image->swap_page) {
pr_err("Could not allocate swap buffer\n");
- goto out_free;
+ goto out_free_control_pages;
}
*rimage = image;
return 0;
-
-out_free:
+out_free_control_pages:
kimage_free_page_list(&image->control_pages);
+out_free_image:
kfree(image);
-out:
return result;
}
@@ -283,19 +316,17 @@ static int kimage_crash_alloc(struct kim
{
int result;
struct kimage *image;
- unsigned long i;
- image = NULL;
/* Verify we have a valid entry point */
- if ((entry < crashk_res.start) || (entry > crashk_res.end)) {
- result = -EADDRNOTAVAIL;
- goto out;
- }
+ if ((entry < crashk_res.start) || (entry > crashk_res.end))
+ return -EADDRNOTAVAIL;
/* Allocate and initialize a controlling structure */
- result = do_kimage_alloc(&image, entry, nr_segments, segments);
- if (result)
- goto out;
+ image = do_kimage_alloc_init();
+ if (!image)
+ return -ENOMEM;
+
+ image->start = entry;
/* Enable the special crash kernel control page
* allocation policy.
@@ -303,25 +334,13 @@ static int kimage_crash_alloc(struct kim
image->control_page = crashk_res.start;
image->type = KEXEC_TYPE_CRASH;
- /*
- * Verify we have good destination addresses. Normally
- * the caller is responsible for making certain we don't
- * attempt to load the new image into invalid or reserved
- * areas of RAM. But crash kernels are preloaded into a
- * reserved area of ram. We must ensure the addresses
- * are in the reserved area otherwise preloading the
- * kernel could corrupt things.
- */
- result = -EADDRNOTAVAIL;
- for (i = 0; i < nr_segments; i++) {
- unsigned long mstart, mend;
+ result = copy_user_segment_list(image, nr_segments, segments);
+ if (result)
+ goto out_free_image;
- mstart = image->segment[i].mem;
- mend = mstart + image->segment[i].memsz - 1;
- /* Ensure we are within the crash kernel limits */
- if ((mstart < crashk_res.start) || (mend > crashk_res.end))
- goto out_free;
- }
+ result = sanity_check_segment_list(image);
+ if (result)
+ goto out_free_image;
/*
* Find a location for the control code buffer, and add
@@ -333,15 +352,14 @@ static int kimage_crash_alloc(struct kim
get_order(KEXEC_CONTROL_PAGE_SIZE));
if (!image->control_code_page) {
pr_err("Could not allocate control_code_buffer\n");
- goto out_free;
+ goto out_free_image;
}
*rimage = image;
return 0;
-out_free:
+out_free_image:
kfree(image);
-out:
return result;
}
_
Patches currently in -mm which might be from vgoyal@xxxxxxxxxx are
origin.patch
bin2c-move-bin2c-in-scripts-basic.patch
kernel-build-bin2c-based-on-config-option-config_build_bin2c.patch
kexec-rename-unusebale_pages-to-unusable_pages.patch
kexec-move-segment-verification-code-in-a-separate-function.patch
kexec-use-common-function-for-kimage_normal_alloc-and-kimage_crash_alloc.patch
resource-provide-new-functions-to-walk-through-resources.patch
kexec-make-kexec_segment-user-buffer-pointer-a-union.patch
kexec-new-syscall-kexec_file_load-declaration.patch
kexec-implementation-of-new-syscall-kexec_file_load.patch
purgatory-sha256-provide-implementation-of-sha256-in-purgaotory-context.patch
purgatory-core-purgatory-functionality.patch
kexec-load-and-relocate-purgatory-at-kernel-load-time.patch
kexec-bzimage64-support-for-loading-bzimage-using-64bit-entry.patch
kexec-support-for-kexec-on-panic-using-new-system-call.patch
kexec-support-kexec-kdump-on-efi-systems.patch
linux-next.patch
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