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authorGustavo A. R. Silva2020-03-23 17:03:49 -0500
committerGustavo A. R. Silva2020-04-18 15:44:54 -0500
commit1fa0949bede6de2b595da535c3ce69de8e130db2 (patch)
tree67d310a16690caf710e5b70e40cc1d7051c77861
parente76018cb604ace486de9cf85898c14bb2b47faff (diff)
digsig.h: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
-rw-r--r--include/linux/digsig.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/digsig.h b/include/linux/digsig.h
index 594fc66a395a..2ace69e41088 100644
--- a/include/linux/digsig.h
+++ b/include/linux/digsig.h
@@ -29,7 +29,7 @@ struct pubkey_hdr {
uint32_t timestamp; /* key made, always 0 for now */
uint8_t algo;
uint8_t nmpi;
- char mpi[0];
+ char mpi[];
} __packed;
struct signature_hdr {
@@ -39,7 +39,7 @@ struct signature_hdr {
uint8_t hash;
uint8_t keyid[8];
uint8_t nmpi;
- char mpi[0];
+ char mpi[];
} __packed;
#if defined(CONFIG_SIGNATURE) || defined(CONFIG_SIGNATURE_MODULE)