bpf: Update the bpf_prog_calc_tag to use SHA256

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Exclusive maps restrict map access to specific programs using a hash.
The current hash used for this is SHA1, which is prone to collisions.
This patch uses SHA256, which  is more resilient against
collisions. This new hash is stored in bpf_prog and used by the verifier
to determine if a program can access a given exclusive map.

The original 64-bit tags are kept, as they are used by users as a short,
possibly colliding program identifier for non-security purposes.

Signed-off-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20250914215141.15144-2-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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KP Singh 2025-09-14 23:51:30 +02:00 • committed by Alexei Starovoitov

parent 3547a61ee2

commit 603b441623

3 changed files with 8 additions and 5 deletions

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6

include/linux/bpf.h

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2

kernel/bpf/Kconfig

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5

kernel/bpf/core.c

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