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Replace one-element array with flex-array member in drivers/xen/xen-front-pgdir-shbuf.c #255

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GustavoARSilva opened this issue Feb 3, 2023 · 1 comment
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Replace one-element array with flex-array member in drivers/xen/xen-front-pgdir-shbuf.c #255

GustavoARSilva opened this issue Feb 3, 2023 · 1 comment
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1-element array arg in memcpy() [Idiom] fake flexible array [PATCH] Exists A patch exists to address the issue [Refactor] 1-element array Conversion away from one-element array

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@GustavoARSilva
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drivers/xen/xen-front-pgdir-shbuf.c:
 30 struct xen_page_directory {
 31         grant_ref_t gref_dir_next_page;
 32 #define XEN_GREF_LIST_END       0
 33         grant_ref_t gref[1]; /* Variable length */
 34 };

Also, worth noting is that this fake flex-array is currently being used as argument in calls to memcpy():

drivers/xen/xen-front-pgdir-shbuf.c-384-                memcpy(&page_dir->gref, &buf->grefs[cur_gref],
drivers/xen/xen-front-pgdir-shbuf.c-385-                       to_copy * sizeof(grant_ref_t));
@GustavoARSilva GustavoARSilva self-assigned this Feb 3, 2023
@GustavoARSilva GustavoARSilva added the [PATCH] Exists A patch exists to address the issue label Feb 3, 2023
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Feb 14, 2023
@GustavoARSilva @jgross1
xen: Replace one-element array with flexible-array member
9a0450a 
One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element array with flexible-array
member in struct xen_page_directory.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

This results in no differences in binary output.

Link: KSPP#79
Link: KSPP#255
Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/Y9xjN6Wa3VslgXeX@work
Signed-off-by: Juergen Gross <jgross@suse.com>
@GustavoARSilva
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In mainline now.

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1-element array arg in memcpy() [Idiom] fake flexible array [PATCH] Exists A patch exists to address the issue [Refactor] 1-element array Conversion away from one-element array
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