Skip to content

net: Avoid directly accessing address of unaligned struct #92459

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Merged
merged 7 commits into from
Jul 1, 2025
Merged

net: Avoid directly accessing address of unaligned struct #92459

merged 7 commits into from
Jul 1, 2025

Conversation

@aescolar
Copy link
Member

@aescolar aescolar commented Jul 1, 2025 

toolchain/gcc.h: Add macro to get address of unaligned member

In principle getting the address of an unaligned structure member
is undefined behaviour, and clang warns as much.
Let's provide a macro which can return such an address.

subsys/net/ip/tcp: Avoid directly accessing address of unaligned struct

Use UNALIGNED_MEMBER_ADDR when getting the address of possibly
unaligned structures members instead of attempting to directly
get the address as an offset.

subsys/net/l2/ieee802154: Do not access addr of unaligned struct

Use UNALIGNED_MEMBER_ADDR when getting the address of possibly
unaligned structures members instead of attempting to directly
get the address as an offset.

jukkar
jukkar reviewed Jul 1, 2025
View reviewed changes
include/zephyr/toolchain/gcc.h Outdated

#endif

#define UNALIGNED_MEMBER_ADDR(_var, _member) ((__typeof__(_var->_member) *) \
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Should we really introduce this kind of macros if they provide access to unaligned member? @rlubos is currently fixing issues reported by UBSAN in part of #90882

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yes, but these are new warnings generated by Clang, and not part of the UBSAN runtime checks. Essentially this is an extension to:
#39192

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Additional explanation: here clang is essentially saying "you are creating a pointer to a uint16_t that is not properly 2-byte aligned, careful with what you will do with it". This is a bit different from other cases where this macro (and UBSAN issues like the ones in #90954) where we were placing non-packed structs inside a packed one. In this case this is a native type (uint16_t) inside a packed struct.

carlescufi
carlescufi previously approved these changes Jul 1, 2025
View reviewed changes
@aescolar
toolchain/gcc.h: Add macro to get address of unaligned member
0f3fbd5 
In principle getting the address of an unaligned structure member
is undefined behaviour, and clang warns as much.
Let's provide a macro which can return such an address.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
aescolar added 2 commits July 1, 2025 15:23
@aescolar
net: tcp: Avoid directly accessing address of unaligned struct
4f9b252 
Use UNALIGNED_MEMBER_ADDR when getting the address of possibly
unaligned structures members instead of attempting to directly
get the address as an offset.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
@aescolar
net: ieee802154: Do not access addr of unaligned struct
bbc0514 
Use UNALIGNED_MEMBER_ADDR when getting the address of possibly
unaligned structures members instead of attempting to directly
get the address as an offset.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
rlubos
rlubos previously approved these changes Jul 1, 2025
View reviewed changes
jukkar
jukkar previously approved these changes Jul 1, 2025
View reviewed changes
@aescolar aescolar added this to the v4.2.0 milestone Jul 1, 2025
@aescolar aescolar mentioned this pull request Jul 1, 2025
Merged
@carlescufi carlescufi added bug The issue is a bug, or the PR is fixing a bug Hotfix Fix for issues blocking development, i.e. upstream CI issues, tests failing in upstream CI , etc. labels Jul 1, 2025
carlescufi
carlescufi previously approved these changes Jul 1, 2025
View reviewed changes
@aescolar
net: igmp: Avoid directly accessing address of unaligned struct
10b7392 
Use UNALIGNED_MEMBER_ADDR when getting the address of possibly
unaligned structures members instead of attempting to directly
get the address as an offset.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
@aescolar aescolar dismissed stale reviews from jukkar and rlubos via 10b7392 July 1, 2025 13:38
aescolar added 3 commits July 1, 2025 15:46
@aescolar
net: http_server: Avoid directly accessing address of unaligned struct
1967c4a 
Use UNALIGNED_MEMBER_ADDR when getting the address of possibly
unaligned structures members instead of attempting to directly
get the address as an offset.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
@aescolar
net: dhcpv6: Avoid directly accessing address of unaligned struct
c68267d 
Use UNALIGNED_MEMBER_ADDR when getting the address of possibly
unaligned structures members instead of attempting to directly
get the address as an offset.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
@aescolar
tests/net: dhcpv6: Avoid directly accessing address of unaligned struct
c90507c 
Use UNALIGNED_MEMBER_ADDR when getting the address of possibly
unaligned structures members instead of attempting to directly
get the address as an offset.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
@aescolar aescolar changed the title subsys/net/ip/tcp: Avoid directly accessing address of unaligned struct net: Avoid directly accessing address of unaligned struct Jul 1, 2025
@github-actions github-actions bot added the area: HTTP HTTP client/server support label Jul 1, 2025
@github-actions github-actions bot requested a review from mrodgers-witekio July 1, 2025 13:49
@sonarqubecloud
Copy link

sonarqubecloud bot commented Jul 1, 2025

Quality Gate Passed Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

@danieldegrasse danieldegrasse merged commit 35a1093 into zephyrproject-rtos:main Jul 1, 2025
30 checks passed
@aescolar aescolar deleted the net_unalign branch July 1, 2025 18:49
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@jukkar jukkar jukkar approved these changes

@rlubos rlubos rlubos approved these changes

@danieldegrasse danieldegrasse danieldegrasse approved these changes

@carlescufi carlescufi carlescufi left review comments

@pdgendt pdgendt Awaiting requested review from pdgendt

@ssharks ssharks Awaiting requested review from ssharks

@stephanosio stephanosio Awaiting requested review from stephanosio

@tejlmand tejlmand Awaiting requested review from tejlmand

@mrodgers-witekio mrodgers-witekio Awaiting requested review from mrodgers-witekio

Assignees

@jukkar jukkar

@rlubos rlubos

Labels

area: HTTP HTTP client/server support area: IEEE 802.15.4 area: Networking area: Toolchains Toolchains bug The issue is a bug, or the PR is fixing a bug Hotfix Fix for issues blocking development, i.e. upstream CI issues, tests failing in upstream CI , etc.

Projects

None yet

Milestone

v4.2.0

Development

Successfully merging this pull request may close these issues.

5 participants

@aescolar @jukkar @carlescufi @rlubos @danieldegrasse