Feeds

Unsafe at any speed: Memcpy() banished in Redmond

Larry? Steve? Linus?

The essential guide to IT transformation

Memcpy() and brethren, your days are numbered. At least in development shops that aspire to secure coding.

Microsoft plans to formally banish the popular programming function that's been responsible for an untold number of security vulnerabilities over the years, not just in Windows but in countless other applications based on the C language. Effective later this year, Microsoft will add memcpy(), CopyMemory(), and RtlCopyMemory() to its list of function calls banned under its secure development lifecycle.

Memcpy has long served as a basic staple of C-based languages, providing a simple way to copy the contents from one chunk of memory to another. Its drawback comes when the source to be copied contains more bytes than its destination, creating overflows that present attackers with opportunities to remotely execute code in the underlying application.

"That's definitely one of those notoriously dangerous C commands," said Johannes Ullrich, CTO of the SANS Institute, who teaches secure coding classes to developers. He likened memcpy() to other risky functions such as strcpy() and strcat(), which Microsoft has already banned after exacting untold misery over the years.

Developers who want to be SDL compliant will instead have to replace memcpy() functions with memcpy_s, a newer command that takes an additional parameter delineating the size of the destination buffer. The command is already supported in Microsoft's Visual C++, but according to Ullrich, native support doesn't yet seem to be available in the GCC compiler. (This evidently can easily be worked around, according to this discussion. Readers who know other approaches are encouraged to leave a comment.)

A Microsoft blog entry that heralded the planned change suggests modifying common header files so compilers issue a warning each time the banned function is used.

It also wondered aloud when "Larry, Steve, and Linus" plan to issue similar security edicts in their products. It's a question worth asking. ®

Next gen security for virtualised datacentres

More from The Register

next story
Snowden on NSA's MonsterMind TERROR: It may trigger cyberwar
Plus: Syria's internet going down? That was a US cock-up
Who needs hackers? 'Password1' opens a third of all biz doors
GPU-powered pen test yields more bad news about defences and passwords
e-Borders fiasco: Brits stung for £224m after US IT giant sues UK govt
Defeat to Raytheon branded 'catastrophic result'
Microsoft cries UNINSTALL in the wake of Blue Screens of Death™
Cache crash causes contained choloric calamity
Germany 'accidentally' snooped on John Kerry and Hillary Clinton
Dragnet surveillance picks up EVERYTHING, USA, m'kay?
Linux kernel devs made to finger their dongles before contributing code
Two-factor auth enabled for Kernel.org repositories
prev story

Whitepapers

5 things you didn’t know about cloud backup
IT departments are embracing cloud backup, but there’s a lot you need to know before choosing a service provider. Learn all the critical things you need to know.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.
Rethinking backup and recovery in the modern data center
Combining intelligence, operational analytics, and automation to enable efficient, data-driven IT organizations using the HP ABR approach.
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.