diff mbox series

[v2,09/16] coredump: Proactively round up to kmalloc bucket size

Message ID 20220923202822.2667581-10-keescook@chromium.org (mailing list archive)
State Not Applicable
Headers show
Series slab: Introduce kmalloc_size_roundup() | expand

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netdev/tree_selection success Guessed tree name to be net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count fail Series longer than 15 patches (and no cover letter)
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 6 this patch: 6
netdev/cc_maintainers warning 3 maintainers not CCed: trix@redhat.com viro@zeniv.linux.org.uk nathan@kernel.org
netdev/build_clang success Errors and warnings before: 5 this patch: 5
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
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Commit Message

Kees Cook Sept. 23, 2022, 8:28 p.m. UTC 
Instead of discovering the kmalloc bucket size _after_ allocation, round
up proactively so the allocation is explicitly made for the full size,
allowing the compiler to correctly reason about the resulting size of
the buffer through the existing __alloc_size() hint.

Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/coredump.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/fs/coredump.c b/fs/coredump.c
index 9f4aae202109..0894b2c35d98 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -68,7 +68,10 @@  struct core_name {
 
 static int expand_corename(struct core_name *cn, int size)
 {
-	char *corename = krealloc(cn->corename, size, GFP_KERNEL);
+	char *corename;
+
+	size = kmalloc_size_roundup(size);
+	corename = krealloc(cn->corename, size, GFP_KERNEL);
 
 	if (!corename)
 		return -ENOMEM;
@@ -76,7 +79,7 @@  static int expand_corename(struct core_name *cn, int size)
 	if (size > core_name_size) /* racy but harmless */
 		core_name_size = size;
 
-	cn->size = ksize(corename);
+	cn->size = size;
 	cn->corename = corename;
 	return 0;
 }