diff mbox series

[net-next,v2,7/7] net: ipa: avoid field overflow

Message ID 20210205143829.16271-8-elder@linaro.org (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: ipa: a mix of small improvements | expand

Checks

Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for net-next
netdev/subject_prefix success Link
netdev/cc_maintainers success CCed 4 of 4 maintainers
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 24 this patch: 24
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 44 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Alex Elder Feb. 5, 2021, 2:38 p.m. UTC
It's possible that the length passed to ipa_header_size_encoded()
is larger than what can be represented by the HDR_LEN field alone
(starting with IPA v4.5).  If we attempted that, u32_encode_bits()
would trigger a build-time error.

Avoid this problem by masking off high-order bits of the value
encoded as the lower portion of the header length.

The same sort of problem exists in ipa_metadata_offset_encoded(),
so implement the same fix there.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_reg.h | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ipa/ipa_reg.h b/drivers/net/ipa/ipa_reg.h
index e6b0827a244ec..732e691e9aa62 100644
--- a/drivers/net/ipa/ipa_reg.h
+++ b/drivers/net/ipa/ipa_reg.h
@@ -408,15 +408,18 @@  enum ipa_cs_offload_en {
 static inline u32 ipa_header_size_encoded(enum ipa_version version,
 					  u32 header_size)
 {
+	u32 size = header_size & field_mask(HDR_LEN_FMASK);
 	u32 val;
 
-	val = u32_encode_bits(header_size, HDR_LEN_FMASK);
-	if (version < IPA_VERSION_4_5)
+	val = u32_encode_bits(size, HDR_LEN_FMASK);
+	if (version < IPA_VERSION_4_5) {
+		/* ipa_assert(header_size == size); */
 		return val;
+	}
 
 	/* IPA v4.5 adds a few more most-significant bits */
-	header_size >>= hweight32(HDR_LEN_FMASK);
-	val |= u32_encode_bits(header_size, HDR_LEN_MSB_FMASK);
+	size = header_size >> hweight32(HDR_LEN_FMASK);
+	val |= u32_encode_bits(size, HDR_LEN_MSB_FMASK);
 
 	return val;
 }
@@ -425,15 +428,18 @@  static inline u32 ipa_header_size_encoded(enum ipa_version version,
 static inline u32 ipa_metadata_offset_encoded(enum ipa_version version,
 					      u32 offset)
 {
+	u32 off = offset & field_mask(HDR_OFST_METADATA_FMASK);
 	u32 val;
 
-	val = u32_encode_bits(offset, HDR_OFST_METADATA_FMASK);
-	if (version < IPA_VERSION_4_5)
+	val = u32_encode_bits(off, HDR_OFST_METADATA_FMASK);
+	if (version < IPA_VERSION_4_5) {
+		/* ipa_assert(offset == off); */
 		return val;
+	}
 
 	/* IPA v4.5 adds a few more most-significant bits */
-	offset >>= hweight32(HDR_OFST_METADATA_FMASK);
-	val |= u32_encode_bits(offset, HDR_OFST_METADATA_MSB_FMASK);
+	off = offset >> hweight32(HDR_OFST_METADATA_FMASK);
+	val |= u32_encode_bits(off, HDR_OFST_METADATA_MSB_FMASK);
 
 	return val;
 }