1493155 - strncpy output truncated - warning

Status: RESOLVED FIXED

(NSPR :: NSPR, defect)

Description

[Alexander Scheel]

Attachment: nspr-strncpy-memcpy.patch

User Agent: Mozilla/5.0 (X11; Fedora; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36

Steps to reproduce:

1. Followed build instructions in JSS for building with upstream NSPR and NSS -- https://github.com/dogtagpki/jss -- (1)(a)
2. Looked at the output during the NSPR build.
3. Look at NSPR upstream source to verify that this is valid: https://hg.mozilla.org/projects/nspr/file/tip/config/nsinstall.c#l520


Actual results:

Received a warning about strncpy truncation:


cc -o nsinstall.o -c      -Wall -pthread -g -fno-inline -fPIC  -UNDEBUG -DDEBUG_jss -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DDEBUG=1 -DHAVE_VISIBILITY_HIDDEN_ATTRIBUTE=1 -DHAVE_VISIBILITY_PRAGMA=1 -DXP_UNIX=1 -D_GNU_SOURCE=1 -DHAVE_FCNTL_FILE_LOCKING=1 -DHAVE_POINTER_LOCALTIME_R=1 -DLINUX=1 -DHAVE_DLADDR=1 -DHAVE_LCHOWN=1 -DHAVE_SETPRIORITY=1 -DHAVE_STRERROR=1 -DHAVE_SYSCALL=1 -DHAVE_SECURE_GETENV=1 -D_REENTRANT=1 -DFORCE_PR_LOG -D_PR_PTHREADS -UHAVE_CVAR_BUILT_ON_SEM   ../../config/nsinstall.c
../../config/nsinstall.c: In function ‘reversepath’:
../../config/nsinstall.c:520:6: warning: ‘strncpy’ output truncated before terminating nul copying 3 bytes from a string of the same length [-Wstringop-truncation]
      strncpy(cp, "../", 3);
      ^~~~~~~~~~~~~~~~~~~~~
cc  nsinstall.o   -o nsinstall


Expected results:

No warning about strcpy; this can be fixed by switching to memcpy.

This was discovered while reviewing and fixing a similar issue in jss code. It appears that nss had previously published this fix as well: https://bugzilla.mozilla.org/show_bug.cgi?id=1438426

JSS issue: https://pagure.io/jss/issue/21 
JSS PR: https://github.com/dogtagpki/jss/pull/24



Apologies if the patch is in the wrong format -- it is my first time submitting a patch with hg. :)

Comment 1

[J.C. Jones [:jcj] (he/him)]

Comment on attachment 9010934 [details] [diff] [review]
nspr-strncpy-memcpy.patch

Review of attachment 9010934 [details] [diff] [review]:
-----------------------------------------------------------------

Looks good to me, thank you!

Comment 2

[J.C. Jones [:jcj] (he/him)]

https://hg.mozilla.org/projects/nspr/rev/b7831176915bc63d531d6b25c9f4e7fcb9405205