From 06ed6aa56ffac9241e03a24649e8d048f8f1b10c Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Thu, 7 May 2020 14:05:49 -0500 Subject: [PATCH 1/2] pcmcia: Replace zero-length array with flexible-array 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] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. 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 Signed-off-by: Dominik Brodowski --- include/pcmcia/cistpl.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/pcmcia/cistpl.h b/include/pcmcia/cistpl.h index 59a011101e0e6..749320cc9aba9 100644 --- a/include/pcmcia/cistpl.h +++ b/include/pcmcia/cistpl.h @@ -161,7 +161,7 @@ typedef struct cistpl_funcid_t { typedef struct cistpl_funce_t { u_char type; - u_char data[0]; + u_char data[]; } cistpl_funce_t; /*====================================================================== @@ -255,7 +255,7 @@ typedef struct cistpl_data_serv_t { u_char escape; u_char encrypt; u_char misc_features; - u_char ccitt_code[0]; + u_char ccitt_code[]; } cistpl_data_serv_t; typedef struct cistpl_fax_serv_t { @@ -265,7 +265,7 @@ typedef struct cistpl_fax_serv_t { u_char encrypt; u_char features_0; u_char features_1; - u_char ccitt_code[0]; + u_char ccitt_code[]; } cistpl_fax_serv_t; typedef struct cistpl_voice_serv_t { From 46d0797906633d82bd50ef26780ee39fac5d27d6 Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Mon, 18 May 2020 10:58:50 +0200 Subject: [PATCH 2/2] pcmcia: make pccard_loop_tuple() static pccard_loop_tuple() is only used within drivers/pcmcia/pcmcia_cis.c, so make that function static. Signed-off-by: Dominik Brodowski --- drivers/pcmcia/cs_internal.h | 6 ------ drivers/pcmcia/pcmcia_cis.c | 6 +++--- 2 files changed, 3 insertions(+), 9 deletions(-) diff --git a/drivers/pcmcia/cs_internal.h b/drivers/pcmcia/cs_internal.h index fb9b17fa0fb56..580369f3c0b06 100644 --- a/drivers/pcmcia/cs_internal.h +++ b/drivers/pcmcia/cs_internal.h @@ -164,12 +164,6 @@ int pcmcia_replace_cis(struct pcmcia_socket *s, int pccard_validate_cis(struct pcmcia_socket *s, unsigned int *count); int verify_cis_cache(struct pcmcia_socket *s); -int pccard_loop_tuple(struct pcmcia_socket *s, unsigned int function, - cisdata_t code, cisparse_t *parse, void *priv_data, - int (*loop_tuple) (tuple_t *tuple, - cisparse_t *parse, - void *priv_data)); - int pccard_get_first_tuple(struct pcmcia_socket *s, unsigned int function, tuple_t *tuple); diff --git a/drivers/pcmcia/pcmcia_cis.c b/drivers/pcmcia/pcmcia_cis.c index b553f7ab532f0..e4c4daf92038c 100644 --- a/drivers/pcmcia/pcmcia_cis.c +++ b/drivers/pcmcia/pcmcia_cis.c @@ -78,9 +78,9 @@ int pccard_read_tuple(struct pcmcia_socket *s, unsigned int function, * calls the @loop_tuple function for each entry. If the call to @loop_tuple * returns 0, the loop exits. Returns 0 on success or errorcode otherwise. */ -int pccard_loop_tuple(struct pcmcia_socket *s, unsigned int function, - cisdata_t code, cisparse_t *parse, void *priv_data, - int (*loop_tuple) (tuple_t *tuple, +static int pccard_loop_tuple(struct pcmcia_socket *s, unsigned int function, + cisdata_t code, cisparse_t *parse, void *priv_data, + int (*loop_tuple) (tuple_t *tuple, cisparse_t *parse, void *priv_data)) {