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Y. Srinivasan" , Haiyang Zhang , Wei Liu , linux-hyperv@vger.kernel.org Subject: [RFC 07/10] hv: Use free_decrypted_pages() Date: Tue, 17 Oct 2023 13:25:02 -0700 Message-Id: <20231017202505.340906-8-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231017202505.340906-1-rick.p.edgecombe@intel.com> References: <20231017202505.340906-1-rick.p.edgecombe@intel.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 25CC74001A X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: b98cen4jzpmjmxwzqm8u4nsc7ixsa1hq X-HE-Tag: 1697574335-276312 X-HE-Meta: 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 4nq1txs1 7edyBteZFUCv1sWzS3SYzwo8aMJ+Ut3OPdlPB2D5iZT7D5QFvKiwZjsNLavdEZLgK7CdfKaXfK5vS2rAlML4DLoEf2/ZiSRiKCv2Rl2dGGrSeYD1eRlyxsp7H2e0o+WPcN2MDjNs5IALHL72Dm24HhbbawNRGOVy8HBnffRTsdyh3oYj8pXalY1oI0lY/2Vswc4Do456omnZloyW913iMUKtABIXKcOoF7WEB6UT+Y+dq7C/Rc6mo2kP3E0GqlRcNF72FlvTGlA9dpXOtextM7eivP/w8oSgN5qi3 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On TDX it is possible for the untrusted host to cause set_memory_encrypted() or set_memory_decrypted() to fail such that an error is returned and the resulting memory is shared. Callers need to take care to handle these errors to avoid returning decrypted (shared) memory to the page allocator, which could lead to functional or security issues. Hyperv could free decrypted/shared pages if set_memory_decrypted() fails. Use the recently added free_decrypted_pages() to avoid this. Only compile tested. Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Wei Liu Cc: Dexuan Cui Cc: linux-hyperv@vger.kernel.org Signed-off-by: Rick Edgecombe --- drivers/hv/channel.c | 7 ++++--- drivers/hv/connection.c | 13 +++++++++---- 2 files changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index 56f7e06c673e..1ad8f7fabe06 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -153,9 +153,10 @@ void vmbus_free_ring(struct vmbus_channel *channel) hv_ringbuffer_cleanup(&channel->inbound); if (channel->ringbuffer_page) { - __free_pages(channel->ringbuffer_page, - get_order(channel->ringbuffer_pagecount - << PAGE_SHIFT)); + int order = get_order(channel->ringbuffer_pagecount << PAGE_SHIFT); + unsigned long addr = (unsigned long)page_address(channel->ringbuffer_page); + + free_decrypted_pages(addr, order); channel->ringbuffer_page = NULL; } } diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c index 3cabeeabb1ca..cffad9b139d3 100644 --- a/drivers/hv/connection.c +++ b/drivers/hv/connection.c @@ -315,6 +315,7 @@ int vmbus_connect(void) void vmbus_disconnect(void) { + int ret; /* * First send the unload request to the host. */ @@ -337,11 +338,15 @@ void vmbus_disconnect(void) vmbus_connection.int_page = NULL; } - set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], 1); - set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], 1); + ret = set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], 1); + ret |= set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], 1); - hv_free_hyperv_page(vmbus_connection.monitor_pages[0]); - hv_free_hyperv_page(vmbus_connection.monitor_pages[1]); + if (!ret) { + hv_free_hyperv_page(vmbus_connection.monitor_pages[0]); + hv_free_hyperv_page(vmbus_connection.monitor_pages[1]); + } else { + WARN_ONCE(1, "Failed to re-encrypt memory before freeing, leaking pages!\n"); + } vmbus_connection.monitor_pages[0] = NULL; vmbus_connection.monitor_pages[1] = NULL; }