From: Nathan Chancellor nathan@kernel.org
[ Upstream commit 3d75e766b58a7410d4e835c534e1b4664a8f62d0 ]
With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A proposed warning in clang aims to catch these at compile time, which reveals:
drivers/scsi/elx/libefc/efc_node.c:811:22: error: incompatible function pointer types assigning to 'void (*)(struct efc_sm_ctx *, u32, void *)' (aka 'void (*)(struct efc_sm_ctx *, unsigned int, void *)') from 'void (*)(struct efc_sm_ctx *, enum efc_sm_event, void *)' [-Werror,-Wincompatible-function-pointer-types-strict] ctx->current_state = state; ^ ~~~~~ drivers/scsi/elx/libefc/efc_node.c:878:21: error: incompatible function pointer types assigning to 'void (*)(struct efc_sm_ctx *, u32, void *)' (aka 'void (*)(struct efc_sm_ctx *, unsigned int, void *)') from 'void (*)(struct efc_sm_ctx *, enum efc_sm_event, void *)' [-Werror,-Wincompatible-function-pointer-types-strict] node->nodedb_state = state; ^ ~~~~~ drivers/scsi/elx/libefc/efc_node.c:905:6: error: incompatible function pointer types assigning to 'void (*)(struct efc_sm_ctx *, enum efc_sm_event, void *)' from 'void (*)(struct efc_sm_ctx *, u32, void *)' (aka 'void (*)(struct efc_sm_ctx *, unsigned int, void *)') [-Werror,-Wincompatible-function-pointer-types-strict] pf = node->nodedb_state; ^ ~~~~~~~~~~~~~~~~~~
drivers/scsi/elx/libefc/efc_device.c:455:22: error: incompatible function pointer types assigning to 'void (*)(struct efc_sm_ctx *, u32, void *)' (aka 'void (*)(struct efc_sm_ctx *, unsigned int, void *)') from 'void (struct efc_sm_ctx *, enum efc_sm_event, void *)' [-Werror,-Wincompatible-function-pointer-types-strict] node->nodedb_state = __efc_d_init; ^ ~~~~~~~~~~~~
drivers/scsi/elx/libefc/efc_sm.c:41:22: error: incompatible function pointer types assigning to 'void (*)(struct efc_sm_ctx *, u32, void *)' (aka 'void (*)(struct efc_sm_ctx *, unsigned int, void *)') from 'void (*)(struct efc_sm_ctx *, enum efc_sm_event, void *)' [-Werror,-Wincompatible-function-pointer-types-strict] ctx->current_state = state; ^ ~~~~~
The type of the second parameter in the prototypes of ->current_state() and ->nodedb_state() ('u32') does not match the implementations, which have a second parameter type of 'enum efc_sm_event'. Update the prototypes to have the correct second parameter type, clearing up all the warnings and CFI failures.
Link: https://github.com/ClangBuiltLinux/linux/issues/1750 Reported-by: Sami Tolvanen samitolvanen@google.com Signed-off-by: Nathan Chancellor nathan@kernel.org Link: https://lore.kernel.org/r/20221102161906.2781508-1-nathan@kernel.org Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/elx/libefc/efclib.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/elx/libefc/efclib.h b/drivers/scsi/elx/libefc/efclib.h index ee291cabf7e0..b14e516be7d5 100644 --- a/drivers/scsi/elx/libefc/efclib.h +++ b/drivers/scsi/elx/libefc/efclib.h @@ -58,10 +58,12 @@ enum efc_node_send_ls_acc { #define EFC_LINK_STATUS_UP 0 #define EFC_LINK_STATUS_DOWN 1
+enum efc_sm_event; + /* State machine context header */ struct efc_sm_ctx { void (*current_state)(struct efc_sm_ctx *ctx, - u32 evt, void *arg); + enum efc_sm_event evt, void *arg);
const char *description; void *app; @@ -364,7 +366,7 @@ struct efc_node { int prev_evt;
void (*nodedb_state)(struct efc_sm_ctx *ctx, - u32 evt, void *arg); + enum efc_sm_event evt, void *arg); struct timer_list gidpt_delay_timer; u64 time_last_gidpt_msec;