[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] xen/hypfs: check the return value of snprintf to avoid leaking stack accidently
commit 33bd9c91865b420adec02380c465e81031b0150a Author: Xenia Ragiadakou <burzalodowa@xxxxxxxxx> AuthorDate: Fri Aug 5 08:38:23 2022 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Fri Aug 5 08:38:23 2022 +0200 xen/hypfs: check the return value of snprintf to avoid leaking stack accidently The function snprintf() returns the number of characters that would have been written in the buffer if the buffer size had been sufficiently large, not counting the terminating null character. Hence, the value returned is not guaranteed to be smaller than the buffer size. Check the return value of snprintf() to prevent leaking stack contents to the guest by accident. Also, for debug builds, add an assertion to ensure that the assumption made on the size of the destination buffer still holds. Signed-off-by: Xenia Ragiadakou <burzalodowa@xxxxxxxxx> Reviewed-by: Juergen Gross <jgross@xxxxxxxx> --- xen/common/hypfs.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/xen/common/hypfs.c b/xen/common/hypfs.c index acd258edf2..cdf4ee0171 100644 --- a/xen/common/hypfs.c +++ b/xen/common/hypfs.c @@ -377,6 +377,11 @@ int hypfs_read_dyndir_id_entry(const struct hypfs_entry_dir *template, unsigned int e_namelen, e_len; e_namelen = snprintf(name, sizeof(name), template->e.name, id); + if ( e_namelen >= sizeof(name) ) + { + ASSERT_UNREACHABLE(); + return -ENOBUFS; + } e_len = DIRENTRY_SIZE(e_namelen); direntry.e.pad = 0; direntry.e.type = template->e.type; -- generated by git-patchbot for /home/xen/git/xen.git#master
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