[PATCH v5 2/8] lib: prepare xxhash for preboot environment

From: Nick Terrell
Date: Wed Apr 08 2020 - 17:56:05 EST


From: Nick Terrell <terrelln@xxxxxx>

Don't export symbols if XXH_PREBOOT is defined.

This change is necessary to get xxhash to work in a preboot environment,
which is needed to support zstd-compressed kernels.

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Signed-off-by: Nick Terrell <terrelln@xxxxxx>
---
lib/xxhash.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/lib/xxhash.c b/lib/xxhash.c
index aa61e2a3802f..b4364e011392 100644
--- a/lib/xxhash.c
+++ b/lib/xxhash.c
@@ -80,13 +80,11 @@ void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src)
{
memcpy(dst, src, sizeof(*dst));
}
-EXPORT_SYMBOL(xxh32_copy_state);

void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src)
{
memcpy(dst, src, sizeof(*dst));
}
-EXPORT_SYMBOL(xxh64_copy_state);

/*-***************************
* Simple Hash Functions
@@ -151,7 +149,6 @@ uint32_t xxh32(const void *input, const size_t len, const uint32_t seed)

return h32;
}
-EXPORT_SYMBOL(xxh32);

static uint64_t xxh64_round(uint64_t acc, const uint64_t input)
{
@@ -234,7 +231,6 @@ uint64_t xxh64(const void *input, const size_t len, const uint64_t seed)

return h64;
}
-EXPORT_SYMBOL(xxh64);

/*-**************************************************
* Advanced Hash Functions
@@ -251,7 +247,6 @@ void xxh32_reset(struct xxh32_state *statePtr, const uint32_t seed)
state.v4 = seed - PRIME32_1;
memcpy(statePtr, &state, sizeof(state));
}
-EXPORT_SYMBOL(xxh32_reset);

void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed)
{
@@ -265,7 +260,6 @@ void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed)
state.v4 = seed - PRIME64_1;
memcpy(statePtr, &state, sizeof(state));
}
-EXPORT_SYMBOL(xxh64_reset);

int xxh32_update(struct xxh32_state *state, const void *input, const size_t len)
{
@@ -334,7 +328,6 @@ int xxh32_update(struct xxh32_state *state, const void *input, const size_t len)

return 0;
}
-EXPORT_SYMBOL(xxh32_update);

uint32_t xxh32_digest(const struct xxh32_state *state)
{
@@ -372,7 +365,6 @@ uint32_t xxh32_digest(const struct xxh32_state *state)

return h32;
}
-EXPORT_SYMBOL(xxh32_digest);

int xxh64_update(struct xxh64_state *state, const void *input, const size_t len)
{
@@ -439,7 +431,6 @@ int xxh64_update(struct xxh64_state *state, const void *input, const size_t len)

return 0;
}
-EXPORT_SYMBOL(xxh64_update);

uint64_t xxh64_digest(const struct xxh64_state *state)
{
@@ -494,7 +485,19 @@ uint64_t xxh64_digest(const struct xxh64_state *state)

return h64;
}
+
+#ifndef XXH_PREBOOT
+EXPORT_SYMBOL(xxh32_copy_state);
+EXPORT_SYMBOL(xxh64_copy_state);
+EXPORT_SYMBOL(xxh32);
+EXPORT_SYMBOL(xxh64);
+EXPORT_SYMBOL(xxh32_reset);
+EXPORT_SYMBOL(xxh64_reset);
+EXPORT_SYMBOL(xxh32_update);
+EXPORT_SYMBOL(xxh32_digest);
+EXPORT_SYMBOL(xxh64_update);
EXPORT_SYMBOL(xxh64_digest);

MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("xxHash");
+#endif
--
2.26.0